Who has had an IMS failure?

Porsche makes greater boxer motors, but seems like every one has an Achilles heel (993 SAI, 3.2 valve guides, 2.7 broken studs, 964 leaking head etc). I'm interested in acquiring a water pumper but this known IMS (intermediate shaft) failure issue is giving me pause. So I'm trying to understand how real and widespread this problem is, so please share the following: Yes, I have had an IMS problem (not someone you know, but you) And my solution was a)Repaired (Cost associated please) b)Replaced engine (Cost associated please) c)Got rid of the vehicle (sold, trade, charity, parts vehicle, etc) d)Something else (Please share your story) I realize this topic has been covered numerous times (yes search is my friend), but my hope is to get an answer w/o the hype. Thanks

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+1...Better get a large one so you can get free refills

Never an IMS problem. Just a failed engine due to a cracked head causing an intemix of oil and coolant. Not quite as bad, but not good!

You might of wanted to include the mileage in the survey. Not sure if you can do a double survey. No problem, no leaks either- 99k, (knock on wood)

No engine issues yet, at least no RMS,IMS failures, but like all 911 Porsches (previous SC, 912, current 996) they tend to have oil weepage(sp) issues, both minor and major. So far, my 10 year old 911 has been reliable and most importantly a great car to 'drive'.

47,199 miles today.

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Great idea, so hopefully those who respond YES can give specifics...age, mileage, type driving (city, track, etc).

Sounds pretty simple to what I've read here about what dealers are doing. I haven't done it but I read that all you have to do is remove the seal off of the IMS bearing to allow oil to be introduced to the original bearing. IMO, that would probably save a lot of them or possibly all of them from failing. Imagine it couldn't take long to do it too.

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+1

My car had the engine replaced at 105k for excessive RMS leaks (they kept changing it, and it kept leaking). That engine was a mix of track and street. I have 40k on the new engine (not that new any more) and it has a mix of track and street.

No IMS problems so far (51K)

Not me either. ^^ Hi Jon, ready for the snow? Oh, 52,000 mile on an '03 C4S, tip.

I answered no because I haven't had a problem but I bought the car second hand with a new engine installed several year earlier. I do not know why the engine was replaced. 2002 model 996 C2 new engine in 2005 at 40K miles current milege 85K miles. Car runs great, no funny noises, great throttle, great chassis, crap stereo.

I just rolled 87K on my original motor. I had the RMS replaced at 74K due to a small leak, and they did the intermediate shaft seal at the same time. It runs great - doesn't leak anymore and doesn't burn appreciable amounts of oil.

2000 and I'm about to hit 70k miles. 5000 miles on my last oil change and I used about a tenth of a liter of oil, surprisingly.

On my former 02, the engine was replaced @ ~25000miles just prior to my purchase. I traded it @ 32000miles (no issues).

No IMS issue, original RMS. 50k miles, bought it at 48k with LOTS of Range 1 events in the computer, but zero Range 2. Passed PPI with no issuew, engine pulls hard, no smoke, burns about a quart every 3000+ miles. And LOVIN driving it every day.

Not me specifically, previous owner at about 60K miles.

03 C2. RMS seal replaced at 36K. no IMS issues.

What's the margin of error on this poll? 100%?

I had IMS failure on my 2003 C4 with 11k miles on May 2008. The prior owner kept it as a garage queen. Thankfully I had CPO, Porsche replaced the engine. I'm now at 23k miles (12k on the new engine) and the car is running well and I really enjoy my car but carry the baggage of being concerned of owning a 996 if I didn't have warranty coverage. I can handle a $1k bill as they may occur on a 6 year old car, but I don't need an unexpected $12-$15k bill. In a couple years before warranty runs out, am thinking of stepping into a 997. No advance notice on the failure. It occurred as I was idling in the garage after a highway trip. Sounded just like marbles in a dryer for a 2-3 seconds then abrupt engine shutdown.

Never an IMS problem. My 2001 996C4 had a failed engine due to a cracked head causing an intermix of oil and coolant. I replaced the engine with a (rebuilt/new) factory engine with porsche warranty. The engine had just under 950 hours or 30,000 miles before the oil and coolant mixed and the engine completely seized with a huge could of white smoke signaled its untimely death. motor blew at a DE event... but don't be put off, tracking your Porsche does not contribute to engine failures.IMO I have 10,000 miles on the new engine and its perfect, bonus it can with new starter alternator, a/c compressor, everything except headers.""touch wood...."" Mixed usage of DE track, and street. I'm the second owner, bought the car 5 yrs ago with 18K miles, car was, and is mint. Total cost of engine replacement, labor parts taxes etc, $17K turn key. After i told my wife how much was the hit, she felt left out and wanted a new kitchen which cost me way more than the engine. In retrospec it was a very costly engine...

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At a hundred respondents, it's probably somewhere around +/- 10%, depending on the split. If you were debating a statistician, the question would be less about sample size and more about whether or not this is a random sample of the 996 universe. But in the end, it doesn't matter. Even if the data was perfect, it would still only be historic, not predictive. It's just interesting, that's all.

IMHO, accuracy of this type of poll and sample size will be a rounding error to zero. Furthermore this type of discussion actuallly detracts brand value, and negatively taints ownership of these wonderful cars, and perhaps resale prices...

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How do you figure that? How about the 95%+ of people who never even heard of this site? Any idea how many people responded more than once? How about those who THINK or were told their IMS was the cause of the failure and it was in fact caused by somethig else? Polls like this serve only one purpose. To eat up storage on the server.

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I've agreed with that for years (and been smacked down for it). But, now, the depreciation ship has sailed. All the hype has been priced into the market, and most people who bought in the last couple of years benefited from it. I'd say that today, especially in America, the cost of a nice 996 PLUS a new engine is still a bargain for the car you get.

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Holster your weapon, soldier. I just gave you a theoretical technical answer, and then I volunteered that the randomness of the sample was debatable. If I wanted to fight with you, I'd tell you what kind of oil I use.

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Another point of view: If this discussion convinces one prospective owner to buy an extended warranty for their new pride and joy then it is a worthwhile discussion. Buying one for my 'new' 996... details and pictures soon!

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Thanks for the show of self-restraint. I just meant that if a phenomenon is ongoing and progressive, then a single datum on historic incidence is useless as a predictor of the future. If 10% of engines have failed, this does not mean that 10% of all unfailed engines will fail. It may mean that all of them will eventually fail, or it may mean that all that will fail have already done so, or anything in between. It's a bit like the H1N1 thing: the phenomenon will ultimately occur as a curve, which you can't really predict the shape of until after the rate of infection has peaked. To me, the only useful data would include some correlates to failure. Oh, and a curve would be nice, too. Otherwise, this is what we call in my world being "blinded by the flash of snapshot accounting."

Welcome I figured it would be best if I didn't try for the millionth time to explain basic stats to the masses. Instead, I have determined that people will either worry about the unknown and fall prey to the perception created. Or........you can take the stance I have and just enjoy the #$&^%@&#*^ car and drive it with an ear-to-ear grin

2004 cab. Had the RMS replaced at 45000 miles No IMS problems here.

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Intermix here too at 30k. Now at 45K on factory reman motor. Wondering about Int Shaft more than I'd like. . . At least the 3.2 valve guide problems weren't catastrophic. todd 99 coupe 89 targa - gone 86 coupe - gone

First engine replacement at 7500 miles under warranty for RMS engine block out of spec. Second engine replacement at 59000 miles (52000 on engine) on my nickel due to IMS bearing failure. 2002 C4 cab

No failure but had two confirmed leaky seals.

I don't want to step into the shortfalls of this type of survey - but I do find it interesting that the percent of respondents that had IMS problems has maintained at 8-10% through this whole survey. (n=77 right now) The L&N wedsite should be required reading for anyone interested about IMS problems. These excerpts are really interesting to me- ------------------------------------------------------------------- Recommendations to extend IMS life from website... "What can be done is to change your oil more often. We recommend oil changes for the M96 and later engines (as we do for air-cooled engines) every 5,000 miles. If you track your car, you should change the oil after every race weekend or every other event at the bare minimum and should also consider used oil analysis to monitor the health of your engine. Use a higher viscosity motor oil. There are several Porsche approved oils that are 5w40, rather than Mobil 1 0w40. Use of an oil that isn't API SM-rated with more Zn and P or an oil with moly extreme pressure anti-wear additives may improve engine life. Timken Falex bearing tests tend to indicate increased load capacity and less wear scarring with oils with high levels of moly as documented here and may prolong the IMS bearing life. To learn more about motor oils and which ones might be better for your Boxster, Cayman, or 911 model, click here. On a new or remanufactured engine the only "preventative" measure that can be taken short of our retrofit kits is to remove the seal off the front of the IMS bearing, to allow for better lubrication of the bearing. With proper lubrication and more frequent oil changes, longevity of your original IMS can be greatly extended. Our retrofit kits use ceramic bearings with significantly longer service life and come with seals removed for improved oiling as well." ---------------------------------------------------------- Interesting comment about failure rate from website .... "Thanks to a fellow Porsche Boxster owner who is also a retired bearing engineer who worked for Timken Bearing, we have gained much insight towards the root causes of intermediate shaft failures. Here's the reader's digest version of his bearing analysis and how LN Engineering has used this information in developing its IMS solutions. By their estimates, they figure a 90% survival rate of the bearing used in the IMS at 90,000 miles* - resulting in a staggering 10% failure rate (called the Ll0 life)! *Assuming an average speed of 60mph in top gear." ------------------------------------------------------------------------------------- Comments about IMS seal and lubrication ... "The main problem stems from the use of a sealed bearing. Although the seals are intended to keep oil out of the IMS tube and keep the permanent lubricant in the bearing, neither happens. On engines observant of factory recommended long drain intervals, oil heavily laden from fuel or just dirty from too long of drain intervals provides poor lubrication for the IMS bearing. Even .002% water in the oil can reduce bearing life by up to 48%. Higher moisture levels up to 6% can reduce bearing life by up to 83%. Excessive oil temperatures also have a negative effect on bearing life - the life of the permanent lubricant used in these bearings is cut in half by every 18F increase in temperature - from an uncontaminated life of up to 30 years at 86F to a useful life of only 90 days at 212F! This is why the bearing engineer recommended removing the seal and allowing the engine oil to lubricate the bearing, and why frequent changes are so important. Oils high in ZDDP and moly further improve longevity as suggested in the article referenced above. More info about ball bearings can be found here. Now it gets more technical.... Where the exact reason for IMS failures cannot be known for sure, in the bearing analysis it was noted that bearings used in the IMS position are unusual in that they are double sealed and have outer race rotation. Bearings were found to be void of grease and had light oil in them and wear patterns in the ball grooves indicate marginal lubrication due to the relatively low viscosity of motor oil compared to grease. In addition, conventional class 1 bearings, like the 52100-series bearing steel used in the factory bearings, is typically only stable to 250F, suffering from fatigue and weakening exposed to elevated engine temperatures that slowly affect the bearing's strength over its lifespan. Attempting to reduce engine coolant operating temperatures directly reduces oil temperatures, further improving bearing life! That's why trying to lower the coolant AND oil temperature is so important! Computer simulation of the 6204 bearing showed that only three ***** are under load at any given time. Hertz stress is moderate. Lube film thickness is very small. Ideally it should be greater than the worst surface finish. Speed is not high enough to develop an elastohydrodynamic film to overcome surface finish/film issue. Fatigue life is high due to relative light load but with no EHD film there will be metal/metal contact and wear. With only three ***** under load at any one time the unloaded ***** will be dragged around by the ball separator. When a ball leaves the loaded zone it will tend to be driven into the separator pocket. The engineer’s initial thoughts were that the ball-separator failure led to bearing collapse, but after analysis of said IMS bearings, it would appear that bearing wear/fatigue spalls lead to separator wear and outer race failure. Separator failure and bearing collapse causes catastrophic failure of the mounting bolt(s) and IMS/timing chain components. The first recommendation was to use a bearing without seals and secondly to use a higher viscosity oil (with greater film strength). More frequent changes will also improve lubrication quality. An oil with extreme pressure additives like Moly might also further assist in increasing bearing life. Higher rpms also increases bearing life as this lessens the viscosity requirements of the lubricant to maintain EHD lubrication, also providing a reasonable explanation of the lack of IMS failures in tracked cars or those driven "like they were stolen." Likewise, far more failures are found in engines with low mileage that are garage queens and never driven to their full protential. Further recommendations by the retired Timken engineer are evident in the design of LN Engineering’s IMS upgrade and retrofit kits." -------------------------------------------------------------------- Check out the full article - http://www.lnengineering.com/ims.html (not affiliated) One of my planned Dec projects is to put the 996 on the lift, pull the trans, and check the IMS for play, remove the seal and reassemble for the mean time. Then consider the upgrade possibly in the spring. Also add ZDDP additives when I change the oil. The car has to last at least another 99k. (I'll report back with pics) Just my thoughts - (not my recommendations to anyone else)

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So, does that mean more than 25,000 Porsches have had an IMS failure?

Who knows?- this isn't a scientific survey. BTW 996 production was 175k and includes turbos and GTs.

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But poll is on all 996, 997, 986 and 987's. Therefore, if there was 400,000+ of them made, this poll has convinced me that 32,000+ have failed due to IMS problems. An earlier poll showed about an 8% failure caused by intermix. So, we have now determined that more than 64,000 Porsches have failed just for 2 reasons. It almost make me want to believe the climate statistics being used.

Sorry for the language, but this is one F-up'ed thread!

Well Well -- it might be F-up'ed -- so let that be an incentive for someone to do it better -- for if we do not try to do it better what are we but a bunch of....? no won't say it... not nice... So if this is a poor job (and good on the thread starter for trying) it is time for someone to do a proper job -- and by the previous posts there are a few of you who know stats -- so let's see you do it properly. And -- if it is a 10% death rate over 200,000 miles then that is what it is -- so be it. I have just returned from a 500 mile in 2 day drive around a coast road (Princes Hwy) and wow -- what a car!!!

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Not here it can't. One word....impossible No, not good for starting it as it will go nowhere just like the last million of these IMS "statistic" threads. As a stats professor I can tell you with 100% certainty, the only way to do this properly is to take it OFF rennlist and have access to the population we need to sample. I'll tell you there is NO access to that sample unless you want to do some mission impossible type crap at PCNA.......

Thanks for constructive crit' LVDell. So -- you seem to be saying that do do a proper survey we would need to get Porsche's stats? If that is correct -- is seems you are saying a 100% sample is needed -- and if that is correct then how do pollsters do their work with sample groups? Now I do understand that Mr Phelps is not driving us to we won't get MI orders but how do we get some guidance and direction? Please lead us to the place of understanding. And this gets a bit lateral here -- can an estimation be done by looking at stats like the number of head gaskets produced for 3.4's and 3.6's (could someone id and then ask/search the manufacturer?) and then deduct the No. used for production and the number for the spares shelf. Or -- do you in the US have a law like we have here in Australia where you can get a Court Order seeking information from any "possible" defendant -- to see if there is a product liability case? See below -- regrettably the Aust law is not quite on point -- but we are a bit behind the USA in product liability law so you may have the mechanism. MAGISTRATES' COURT CIVIL PROCEDURE RULES 2009 - SECT 13.03. Discovery to identify a defendant 13.03. Discovery to identify a defendant (1) If an applicant, having made reasonable inquiries, is unable to ascertain the description of a person sufficiently for the purpose of commencing a proceeding in the Court against that person (in this Rule called the person concerned) and it appears that some person has or is likely to have knowledge of facts, or has or is likely to have or has had or is likely to have had in the person's possession any document or thing, tending to assist in such ascertainment, the Court may make an order under paragraph (2). (2) The Court may order that the person, and in the case of a corporation, the corporation by an appropriate officer, must- (a) attend before the Court to be orally examined in relation to the description of the person concerned; (b) make discovery to the applicant of all documents which are or have been in the possession of the person or the corporation relating to the description of the person concerned. (3) If the Court makes an order under paragraph (2)(a), it may order that the person or corporation against whom or which the order is made shall produce to the Court on the examination any document or thing in the person's or the corporation's possession relating to the description of the person concerned.

I never said we need 100% of PCNA's data. We just need access to the population we intend to sample. Sure, access to 100% of the data would be awesome and we could just report basic descriptive results as a number of failures (cause undetermined) per "X" number of motors produced or even total number and percentage. The problem is that you will NEVER get eyes on the PCNA data set. Trying to collect data from Rennlist is a two-fold problem......self-report (full of errors) and zero random sampling even of this convenience sample. I'm not (nor are my other stats colleagues here on RL) going to go over a full stats debate again as this has been talked to death over the last decade. ps. If I had to hypothesize what the number truly is based on what we see here I would say that if the self report data on a website is 10% failure rate then the actual number is probably about 1/10 of 1% IRL.

Totally concur with Dell's comments. I think what gets people wound up about this kind of thread is that bad information is more damaging than no information is, both in terms of the value of the cars and the quality of the ownership experience. Here's the most interesting piece of data I know of: Nobody has ever been able to certify a class against Porsche for this. When you consider the Type-A-ness of the typical Porsche driver, that's remarkable and telling.

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Winner winner chicken dinner!

Guys, I don't know why this thread went so askew and has been purposely diverted to a discussion of statistics. Asking a group of 200-500 996 owner's "who has had an IMS issue", and of those who replied approx 10% said yes and 90% said no -Done. Ask the same question of 997 owners 5% say yes 95% say no. Makes sense, younger car, updated IMS and fewer miles. This is not an end all statistical study on IMS failures but a simple question, take it for what it is. Thank you for everyone who has participated (including those who voted and then went on to condemn and sidetrack it).

You don't know why? You said you did a search right? Fail. Some people just don't get it and either don't realize they don't get it or do and then attack those that try to explain the flaw of a NOT so simple question and how to ask it. But if you feel better asking a question that can have zero empirical support here other than flawed anecdotal water cooler chit chat then you did well. Don't get your panties in a bunch when you are explained why this question has been asked a million times. Why it can be asked no differently for the millionth time. Why your thread is going to do nothing to get any sort of different answer (look up the definition of insanity) than any previous one. Etc, etc, etc.. Drive your car, enjoy it, or sell it if you worry about the hype. Geez, how I keep getting dragged into this crap.

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By your own choice

Good point. I guess I'm a sucker for crap driven by ignorance for which I have a background in. Time to stop thinking I can educate the ignorant. I'm going to go enjoy my car, have fun worrying about the IMS.

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Remember this post LV? For what it's worth I think we have now firmly established that 10% of the 996 associated with Rennlist have had IMS failures. Of course it's been established before, and will likely be established again, but this is what we now know. That's something at least. It's not much, but it's something. I would think it's the high water mark anyway.

Sure do. And trust me, I tried. However, some just never get it and will continue to ask these silly questions. But no, we haven't established that 10% of those on RL have had IMS failures. Remember, this has NEVER been a sampling but rather a voluntary poll. But like I said already, I agree that "if" 10% is the water cooler number for the 996 forum then reality is probably closer to .01%

85,000 miles and no problems. Interesting that your survey results agree w/ Jake Raby's estimates of about 10%. FYI, the IMS problem was not addressed with the 997 until recently, so that 5% may increase with time.

Anybody have any idea how Jake arrived at his number?

Last I heard, my old car (2000 3.4L) far north of 100k still has it's original IMS. Now my '87, well, its wrapped up and preserved right now waiting to be put back in....

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Yeah. It was determined that 10% risk would sell more bearings than 1/10%. It is about as scientific as this survey is.

For me this is an interesting thread -- it is obvious that stats are well beyond those of us who have degrees that did not include a calculator! The best part is seeing that the number is between 0.01% and 10% and for me that's ok because when factored into the cost of the car it makes for sensible buying. And LVDell -- thanks for getting involved -- in reading back over the entire thread -- you did get your message through to me.

Thanks Michael. Very welcome You seem to have a good approach to this. In otherwords, you know what the "perceived" hype is and decided the car is fantastic regardless. No sense in worrying about something so remote and just go out and enjoy it! Happy motoring........

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Ask Jake. But let's face it, he clearly has researched this issue more than anyone I know, and has more experience with it. And quite frankly I don't think he has any significant financial motivation to fudge numbers. I mean, this is a niche part, he's not gonna get rich off of selling 996 IMS replacements to 10% of the owners.

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The point is, what exactly is Jake using as a sample to pull his number out of the air? We already know that NOBODY has the data set to sample from other than PCNA. So his guess is as good as these polls. And yes, he has a serious financial motivation to sell this part as he's not in this as an altruistic venture. He is running a business and he has invested money developing the part as well as advertising trying to sell. We won't even get into his presence on this and other forums stressing the need for this. Remember, he's not just trying to sell an "upgrade" part but he also talks about the need for a better motor and he sells just that.

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Once again, ask Jake. I never said he was altruistic, I just said that he ain't gonna retire off of IMS upgrades.

No desire to ask him but he's welcome to chime in (I doubt he will though). He's running a business so he's not trying to retire off IMS upgrades but rather make a living.

I don't see the point of interrogating him about this. The 10% number has a lot of traction online and off, likely from repetition. I wouldn't blame him for citing it. One of the problems with this whole thing is that we actually don't care how many people have had IMS failures. We care how many cars have had IMS failures. That's always been a secret, and is probably now unknowable as these cars pass on to their second and third owners at prices that are making 996 owners a very mixed demographic bag, more are being tracked and an increasing number of them are being maintained at indies. There's a good chance that even Porsche doesn't know for sure anymore. The truth is that people don't want to know how many have failed. What they really want to know is what their odds of a failure are. The answer is 100% will fail, eventually. The only question is when and at what cost, and that's about as specific and predictable as your own demise.

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I would venture out and say that Jake's number may be baised. How many people would be calling him when they do not have an IMS issue vs when they need help?

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100% correct. It's a moving part that will fail. The point is, which we have been talking about for some time, is how is this a design flaw and how is this a reason to upgrade when the number of failures is so low? Either it's a weak point that WILL fail prematurely or there is something else at play that we have not identified to explain the small number of failures relatively to the perfectly fine units.

If you read the L&N website, they explain ways to extend the life of the IMS without upgrading and also offer the option of the upgrades. I think as a group, we should applaud the work of people that propose solutions to make our cars better, no matter how big or small. Also from the L&N website, it appears that it is the bearing engineer that proposes the 90% "L10 life of the bearing" based on assumptions. (with a sealed bearing in an enviroment that it probably wasn't intended for, and all the many variables, I'm not sure if you can estimate the bearing's expected life) I did read the papers on 'sealed bearings' that are linked on the site, and it does seem clear that this bearing would work much better without the outer seal. They say that oil is a better lubricant for ball bearings that grease (especially if it leaks out). It does mention that you don't want it immersed in oil. Some IMS fail- plan accordingly.

Just to make a further contribution to the squandering of bandwidth... The reason I'm so cavalier about it is that there are some underlying issues that are so fundamental and unmanageable that there's nothing to do but wait and see if you're lucky. In my fevered brain, these are: 1. Porsche was in financial trouble when this car went through production engineering. In the M96 history, there are many examples of both poor materials choices (plastics, most notably) and financially pressured QC (such as the reuse of porous blocks). 2. The decision to use this long, unsupported intermediate shaft was made to save the cost of separate casting for the right and left heads. It was a risky compromise, especially when combined with 1. Again, nothing will change this. 3. These engines were assembled by hand on a bench. It seems logical to me that, when combined with 1 and 2, this would produce more variability than a big mass production carmaker would allow. (If you don't believe this, ask someone how homologation engines are built: the motors are built with hand picked parts from production parts bins, but end up producing far above the rated horsepower for the design. That's how much variability there can be on a component level, even under ideal circumstances.) Put it all together, and you end up with another quirky Porsche engine, of which there have been many... brilliant when it works as designed, but troublesome when it doesn't. Just is what it is.

Those posting IMS problems. Are you posting leakage as a problem or is this thread only counting bearing failures?

Just curious, what does your userid mean?

I was listening to this song years back when registering on a forum. http://www.youtube.com/watch?v=FLCAGDhhcro

Holy adrenaline Batman! I don't need coffee anymore in the morning. I'll just watch that video

LVDell, Had to ask as I'm a newbie. Is the question flawed because not everybody on here answers? A little like, "Have you been to Vegas and if so, did you like it?" Well, if you've not been to Vegas, many will skip the thread most likely, therefore it will look like almost everyone has been to Vegas on the poll?

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Actually... Thats not my number. No one could squeeze an actual number from me if they tried.. They try all the time. Its impossible to make an accurate forecast as to the number of failures because no one knows how many engines were produced, how many have failed or how many were swept under the carpet before the IMS failure was "known about". I will say that we average 7 IMS failure calls per week and have for the past two years. I know that Dean has answered two of those today. People call us on two occasions: -1 When they want more power and reliability 2- When they have a scattered engine. So there is some bias, I do agree.

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Pretty much. The problem is that at no time is a single person sampled from the population. There is only a poll and it's purely voluntary. Further there is zero oversight to determine who is or isn't being truthful. The vast majority of M96 owners do NOT even know about Rennlist. The main people that come here are (1) enthusiasts that enjoy the water cooler talk we have here; and (2) people that have problems with their cars. My guess is that there the failure respondents number is inflated b/c of #2 and the number of perfectly fine IMS numbers are low b/c of sheer numbers of Porsche owners will zero problems that know nothing about this site. There are just too many variables that cannot be controlled for. I'm sure (99.9%) that PCNA has the figure and can state with certainty their margin of error is very small. As has been discussed, the number is probably less than 1% of all M96 motors that have an IMS failure. That's pretty good in my book. If the problem was a bad as the hype makes it out to be there would be a much stronger presence and probably some sort of class action against PCNA and PAG. Remember, the IMS will in fact fail. Just like a water pump and a window switch. They are moving parts.

Ok, how about if we say that we all have a 90-99% chance of our engines NOT blowing up due to a premature IMS failure, how's that? ps. I really don't understand why folks are so hard on Jake all the time. I've gone to the website and I think he and Chris support their positions very well, are very honest and upfront about their products, and are straightforward guys. I applaud them for the research and time they have put into our engines.

People are hard on Jake b/c he has a business to run and product to sell and at the same time fuels the IMS hysteria with his scare tactics. Not good and not welcome in the community. With that said, what he does is great for the community for those people that are interested in those products and upgrades.

Mine is a 2000 996 C2 with currently about 79K miles on the odo. Engine was replaced in 08-2006 by previous owner at 29K miles. Initially running M1 0W40 when it was still my daily driver for about 30K miles. The last year or so main usage is to/from and on the track, running M1 15W50. The car doesn't stop putting a grin on my face each time I get behind the wheel.

In a typical dental practice setting, we might see maybe 20% of patients presenting with fractured teeth. Most of them swear it happened when they were eating something soft, like a ham sandwich or a bowl of soup. Nobody ever says they broke their tooth trying to crack a walnut, on a drunken bet with their buddy. If we crown their teeth with full metal crowns (caps) which are much stronger than tooth enamel, they will not ever fracture. So, following the logic from aftermarket mechanics, we should: a)alert all our patients that, based on what we see coming through the door, they have a very great likelihood of suffering a fractured tooth b)persuade as many of those patients as we can to have all their teeth capped with metal crowns to prevent a fracture from occuring c)inform them that in the interim, they should go ahead and crack walnuts with their teeth because from our data, fractures are much more prevalent in people who eat soup. Of course, any of the above would be considered malpractice, so if the patient is worried that he might someday experience a fractured tooth and will have to pay to repair or replace it, all we can do is encourage him to buy dental insurance from one of the reputable carriers...which for the cost of a single crown, will cover him for a year against a whole host of possible dental problems. Of course we would make more money if we could do a-b-c above. I think I may have chosen the wrong career

Well, if a cracked tooth cost $15 grand out of pocket to fix, and the cap was only $800 to add onto a regular visit, then I would probably at least consider the cap. Let's face it, we all pay insurance thousands of dollars a year so that IF we have a problem/accident we are covered. Car, Home, and Health. The truth is that 80% of the people who pay insurance don't use much if any services in a given year. In my car it's called preventative maintainance. Just another type of insurance. If an $800 IMS retrofit could save $15 Grand, and increase the resale (at least perceived) value, then for some it's well worth it.

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I hear what you're saying. Your comment raises another excellent point. Furthering the analogy, capping one tooth would not fully solve the potential problem, it still leaves the other 31 teeth vulnerable to cracking. For genuine peace of mind you would need to crown all of them, which would cost you tens of thousands. Jake has said himself that a number of blown engines are chalked up to IMS failure when in fact it was actually something else. If my engine blows I will strongly consider a replacement engine built by Jake with all his re-engineered upgrades for the other weak factory components, not just the IMS bearing, rather than a remanufactured engine from Porsche (assuming this was after the CPO expires, because with that I have no choice).

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Ignoring that there is more than one tooth to be dealt with, the probability of a cracked tooth would have to be greater than $800/15,000 = 5.3% for it to make sense to proactively choose the cap, assuming the cap will never fail. Seems like a pretty high threshold to meet....

[QUOTE=Marco8;7115942] So I'm trying to understand how real and widespread this problem is, so please share the following: Yes, I have had an IMS problem (not someone you know, but you) And my solution was a)Repaired (Cost associated please) b)Replaced engine (Cost associated please) c)Got rid of the vehicle (sold, trade, charity, parts vehicle, etc) d)Something else (Please share your story) e) Traded the car last week - Now I can sleep an night! 99C2

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[QUOTE=99C2;7135508] That was a good decision. The only reason to a Porsche is that it's fun. If you're afraid of what it's going to do to you, you're wasting your money.

The IMS bearing Mode Of Failure (MOF) is the most known and most feared of the 20 MOFs that we have documented. Due to this when something breaks and the (M96) inexperienced techs can't find it or just want a scape goat they call it an IMS failure. I have even had some engines that appeared to have an IMS failure when it was actually the IMS chain tensioner paddle that had failed. I've seen three of those this year so far.

If I had an F-car I know that every two years years belts need done. That is just the cost of having the car. Maybe the cost of owning my Porsche is changing the ims bearing every four years?

Well, this month I celebrate the 11th birthday of my 996. So far, no RMS leak, no IMS failure, no intermix, and no D-chunk. Car now has 48,250 miles. It may seem low, but this car is no garage queen. It gets the daily commute a couple times a week, road trips on the weekends, and about 2-3 DE's a year. Does that mean I'm cavalier and don't worry? Nope. I have recently replaced the white plastic coolant container because the original was getting old-looking and my previous other 3 996's all seemed to have that leak eventually. I experienced my first ever A/C compressor failure this past summer (45,000 miles). Replaced with new compressor, and while they had it all apart up there, they also replaced the belt and the aforementioned coolant container because they were already in there with a lot of the stuff off the top of the engine. Preventative maintenance. When either the clutch gets old, or the RMS begins to leak, I will replace the RMS, the IMS bearing, the clutch assembly, the oil pump and the water pump. Why not? They are already going into that area anyway. Eventually these things "might" fail, and doing it for the extra cost of the parts seems logical to me, compared to a failure or a second trip inside. Preventative maintenance. However, the D-chunk thing will just have to happen before I go in there. The car has already had the valve covers resealed many years ago, the oil/water separator replaced, the MAF sensor failure, and many of the other minor "external" engine problems that get discussed here. So, I am not silly enough to believe the remaining unaddressed failures may not happen also. Since my car will never be CPO'd for a future sale (I am a private owner, not a dealership), it just makes sense to me to address these potential issues as a group when one of the symptoms appears. Excellent resale point some day. And far cheaper than a whole new engine. Still, it could be the D-chunk that happens first. Such is life with high-performance cars. If you can't stand the heat, get out of the kitchen. When the day comes that any of my cylinders has a lower compression check, then the D-chunk solution will be addressed. I will not continue to drive the car with a low compression situation. I never ask the question, "How much farther can I drive it like this?" I always say, "What else needs to be done while we are in there?" Get it done before it fails. But use your head.

"Preventive maintenance" is self explanatory. Judging from Thundertub's location and Avatar I'd say he works in the Aviation field... Anyone who has been associated with Aviation knows that every component has a service life and whether the component is good or bad it is still changed as "Preventive Maintenance" procedures. The service life of the components are also not at the maximum life expectancy of the component. And some components operating in high value conditions have a 1/2 service life, meaning they are changed at 1/2 the normal service life, whether necessary or not.

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I would replace them too, if the failure meant a 50,000 ft fall! Jake- Speaking of the 20 MOFs. I'm assuming the 80-20 rule applies. The MOFs that I can think of are, IMS bearing, crack in head, D chunk, chain tensioner, porous cases, hydro lock from water from power brake area, broken crank from light weight FW... others? Leaky RMS & IMS are not MOFs, right? Luckily some of these MOFs can be prevented or were taken care of early on with engine replacements. Vario-cam pads? I replaced these on my 968 @ 100k. Pads had grooves and pitting. Is this something to consider replacing on my 996? 99k. Looks like the chain tensioner could only be replaced with case open?

We only recognize it as an MOF if we've seen it numerous times with the same effects. Some things are just weird incidents that we only see once and those don't count. Like this one..

Ouch!

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Yeah, that would be the DREADED POROUS PISTON failure.

Revisiting the statistical value of this thread, as others point out, a quick and unstructured survey such as this will contain bias or can show mis-leading results for various reasons, but whatever it is that the survey measures, it is measuring with reasonable stability - That is, my recollection as this thread grew is that the IMS failure rate on the poll (once we had say more then 15 responses) has stayed in the 10-15% range through the present where we have > 130 responses. I don't know that this is useful information per se, but I thought the IMS failure rate response stability stood out.

I have kept my mouth shut on this because I don't own a 996 anymore. But, I will say this; to date, 18 people claimed failure. That means if true, 18 engines have failed due to a design flaw of the engine. This failure is not a simple breakdown on the side of the road, this major surgery to fix or replace the engine entirely - whichever the owner chooses. That is why statistically small or large, the impact is immense! If 18 'vette engines failed out of the bazillions made, there would be more bitching about it than you find here. And the LS motors are very simplistic and easy to repair (of course there is no such IMS in a LS motor). It would simply be unacceptable. Do I think there is denial of the severity of the issue of the IMS? Yes So, that being said, does the M96 scare me from another? No, no way. Would I own another if I could? Yep.

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18 failed engines that we "think" were the result of IMS failure is a design flaw that leads to catastrophic failure? If it was a design flaw that leads to failure the result (number of M96 motors failing from this) would be huge.....and that's just not the case. While I certainly sympathize with those have lost a motor due to this, I find it comical that it is blown so far out of proportion like this. Again, if the problem (reality) was so congruent with the hype there would have been a more significant remedy to date (read PCNA recall, class action, etc).

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Your observations are no less speculative than those you seem compelled to debunk at every opportunity (I wonder how many of your 17,000+ posts are in some way related to this issue). Fact is, Jake and others here making the counterpoint have no less of a chance statistically to be right on the money as only PCNA could say for certain. As someone involved in a Porsche exclusive maintenance facility I can only say that we saw an inordinate amount of IMS failures on Boxters and 996's to the extent that it was a known and serious issue amongst factory trained Porsche techs working at the largest dealers in So CA (one of whom then came to my facility with this inside information that affirms the point made.....more cars than you think were affected with the problem). Think what you want and speak for yourself but stop arguing that your observations are any more credible than others and moreover, that you somehow "speak for the community" especially as to how many Porsche owners actually know about this place and/or why they are here.

Thanks again Jordan for your typical attacking post. Either provide this "proof" you seem to have of insider info or contribute something of worth. But your attacking gets old. I have taken a stance that explains WHY this is not a nearly a big of a problem as you and a select few think it is. I can do this through BASIC explanations of statistics. You on the other hand like to try and figure out a way to deflect from the issue by attacking me. And no, I have NEVER tried to debunk this IMS hype. Rather I have explained WHY you can't take the stance you do. Thanks again for your lovely post. Yawn.......... ps. you answered my stance for me. Your side SPECULATES. Thanks for that

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This is my point too Dell, your statistics are no less baseless and you simply need to be politely reminded that your opinions and observations do not relfect the vast majority of Rennlist users or Porsche enthusiasts in general any more than mine do. My obeservations are mine and mine alone and I'm simply sharing them (this includes personally knowing a lot <as in a number greater than 10 locally> owners with IMS failiures and dealer techs some with 30 years experience saying to my face the problem is more widespread with early M96 cars than Porsche let's on). Statistically relevant....no...worth sharing though....I think so as at minimum I tend to trust what my 30 year Porsche tech tells me about these cars. Your modus operendi when anyone shares a similiar experience or posts a question about it is to dismiss them and the point as hysteria or hype. Of course I can't say statistically any more than you can whether the problem is with 1%, less than 1%, 10% or some other figure any more than you can. What I can say for certain though is that my own personal experience with the 1st Porsche I bought at 29 years old (a brand new 1999 996) was less than satisfactory. I spent nearly $80 grand on that car that was rife with build quality issues and it spent so much time in the shop that when it finally detonated due to an IMS failure at 20K miles I was simply stunned (this was in 2001)...and it was a big deal to me. These cars are indeed great deals now and it's not by accident or by hype that's built up by posts on Rennlist. There are books about it, businesses dedicated to it as well as similiar occurences all over the world to the extent that the values of these cars have been severely impacted by it as a result. Had I paid $20 grand for my car and had it happen it might have been a different story. I've ultimately owned 5 911's since that 1st buy and I can say with absolutle certainty (only as it pertains to my own personal 1st hand experience) that the reliability and build quality of the 1999 996 was a distant last to the next closest example with the current 993 I own (perhaps due to the fact that it's the most evolved of the air cooled design) being the best. This is indicative of the logic 'buy the newest Porsche you can afford'. I think the 996 is the best value buy for the money out there likely becuase of what "can" happen. To what % is largely irrelevant because as long as we can all agree it happens to a number greater than zero it's possible - therefore it should be factored in to your decision as that's measurable risk. I have nothing against you or anyone else personally and sincerely appologize if that's your inference from my posts now or in the past. We should all stick to personal experiences and not attacks anyway as this is the spirit of Rennlist is it not?

I've been watching this kind of thread for a while now. I fully expected Dell to jump in. From a party who has no skin in the game I make only the following observations: 1) There is no use arguing statistics since only PAG and PCNA know for sure. Irrespective of our knowledge of stats - there isn't enough info to draw any valid statistical conclusions. 2) Porsche has a long history of burying problems - the 993 wiring harness defect comes to mind here. 3) Too many people have suffered premature engine failures to suit my taste. Are there more of them than say, M3 BMWs? Who knows? We do know that there are thousands and thousands of owners who have not suffered catastrophic engine failures. 4) Porsche has redesigned the engine for the 98 and 99x cars. DFI is certainly part of it but the redesign went far beyond that. 5) Since Jake and friends have invested time and money to come up with fixes and preventative measures, rather than denigrate them, I prefer to thank them for supporting the community. Best,

Dell, it's not the statistics of failure that concerns me, it's the fact the motor may become scrap metal after the bearing fails. Such a simple thing Porsche could of done by using the proven friction bearing of the past or open ball or roller bearing for the IMS could of saved some (whatever the number) of these engines. Now the RMS, thats something that is made a big deal of when it is a simple seal that is relatively cheap minus labor cost to replace. DIY is almost nothing and you are on your way. Like I said, it would be on my mind if I owned another but it wouldn't stop me from owning another.

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Agree 100%. If you please stop attacking me or my post count then I wouldn't have to retort. And yes, my personal experience is statistics. Yours is working in a shop that sees people come in with problems. See where the problem lies for both of us? You have my word that I will not send a personal jab toward you from this day forward. Sorry Bob, but nobody is denigrating anybody for working on upgrades for these cars. We all appreciate what the guys in shops like Jake et al are doing. It's the hype that gets old (see Jake's last ad campaign). Is there a problem with the M96? Sure, we can call a failure a problem. Is it as prevalent as those want it to be? NO WAY TO TELL. That's why you CAN argue statistics. Since there are NONE you can't make the claims you do. That's all and that the POINT that I have been trying to make. Did you miss that? What concerns you is valid...I agree. What concerns me is that people IGNORE basic statistics and make assumptions WITHOUT any way to support it.

Dell, I did not make any CLAIMS, nor was my post as strident as yours. I suggest we all chill a little. As the CI of a very active region I have seen half dozen catastrophic failures of 98x and 996 engines. It strikes me as odd that there have been zero failures of the old 3.0, 3.2 and 3.6 litre engines in the 993. When you figure that the newest engine in the 993 is now 12 years it does make me wonder. A lack of accurate statistics is not a valid reason to dismiss the fact that early 996 engines are somewhat suspect. In Panorama, or Excellence, not sure which, the tech columnist speculates that the odds of failure are one in five. How this was derived, I don't know, since an appropriate data set exists only at Porsche. So I agree that no accurate statistics are available. On the other hand your posts seem to imply that the problem is insignificant. There are no stats to support that position either are there? Regards,

Bob, you are totally not reading my posts. I never said it was insignificant (or properly stated not significant) but rather that you CANNOT state there is a significant problem. That's all, so don't IMPLY what I have said. I have been very clear. I have NEVER said there was no problem. However, I agree, there is something at play. But the hype and hysteria get old. FYI....there is zero chance (I can say that with statistically certainty ) that this is something that everybody will chill from.

In the early 1980's I was a dealer Service Rep for Toyota -- looked after about 40 dealerships and helped with all sort of mechanical issues -- training, warranty, customer complaints etc'. About then Toyota was "cornered" with the Corona because to meet the local content import rules they had to use a 4 cyl GM engine -- it was branded Toyota and sold as "all Toyota", the engine was one problem after another -- but everybody at Toyota said "fix em properly and never say no -- keep the customer happy -- Toyota's reputation is more valuable than the cost of repairs. There were other examples of that "fix it at any cost" to protect the reputation way of thinking. Why is Porsche different? I don't know but I can say that if there has been 1000 engine grenading episodes worldwide in Boxters and 996's then Porsche should be roasted and humiliated and front up and be honest and trustwothy members of this global community and admit and fix -- why they don't is something someone more in tune with German commercial ethics will have to answer. And when those of you who belong to Porsce clubs are meeting and spending good PR time with Porsche exec's you should be repeatedly bringing to their attention the loss of trust we have in them for not admiting fault and fixing the problem.

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Nothing German about it. The math is simple. Let's take a Toyota example (a company I advised for several years): Toyota recently initiated a program to buy back rusting Tacoma pickups built between '95 and '00 at 1.5x book value. Good deal. The program is costing them $100,000,000US. But, remember, Toyota sells about 1.5 million Tacomas worldwide, each year. (This, in turn, is roughly 10% of their total production). So the world's largest car company is exposed to the tune of roughly $400 per unit sold, at the very most, well inside their margins for those vehicles. Porsche, on the other hand, sold an average of less than 20,000 units of the 996 annually during its production run. Even adding in Boxters and Caymans, the exposure is massive, and given their annual production of all models is surely less than 1/100th of what Toyota's is (North American sales are below 30,000 units right now, all models combined), there is no chance of absorbing this. It's a straight up loss, for a company whose balance sheet is already in the toilet. Lawyers would be cheap by comparison. It's not German. It's business. And it's the chance you take when you buy a low-volume car. I'm not saying it's right, but it is what it is.

Thanks BruceC -- good reasoning well put. Still pi**ed off at being treated like this. But -- I thought (dangerous I know) that Porsche's reputation at the time was that it was the world's most profitable car manufacturer. I realise that now it's a toilet job but a few years ago when it would have been the right thing to do (to confess and fix) it was said to be a financial powerhouse. I still get the feeling (hope) that somewhere there is FOI legislation to get the data (or that some disgruntled Porsche employee will leak the failure data -- anybody listening?)

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Who knows. Maybe Volkswagen will do something. They're certainly wealthy enough. On and off over the last several years, Porsche has been the most profitable car company on a unit margin basis, but never on a gross profit basis in its wildest dreams. Whose profits would you rather have? A car company that makes 4% on 15 million units? Or the one that makes 20% on 100,000 (making these numbers up)? People who describe Porsche that way forget that you can't take percentages to the bank.

Aight, Long time lurker and infrequent poster. Simple question. Will LN-Engineering's IMS upgrade prevent the dreaded IMS failure? Thanks,

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No one??

Have you thought about contacting Jake directly and see if this is a guarantee they make?

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I understand your facetious suggestion as there's not an IMS thread without your input.. But as you're aware and I am too, their website states there's no guarantee.

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Nobody knows, or can know. There are two significant factors that don't change if you do the upgrade: the original design of the engine, and the driving and maintenance habits of the owners (many believe that more attention to oiling and to driving smoothly promotes reliability of this and related components). I did the upgrade. Just comparing the parts physically convinced me that I was improving my odds against a failure. But that's it. Odds. No guarantees.

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Lovely reply. If you think I was being facetious then you haven't been around long. As for your suggestions that I already know..... Actually I'm not aware as I have had no desire to change this part on my car so I have never contacted Jake nor checked his site for this. Hence, the reason I asked if you had since you are looking for a answer to this.

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Thanks for a sensible answer.