Help sorting through the IMS hoopla

We've had our March build 01 since new and I've followed the IMS situation over the years with the plan to replace ours the next time we did the clutch (sometime in the next 10k or so). Even so I've had a hard time sorting out the details and really what's best. The latest thing to get me is that our VIN is not in the list for the class action. I know earlier engines were setup differently (and not prone to the failure?) but I thought the change was early or mid 2000. So is our engine still prone (using the term loosely) to an IMS failure or are we good? If it still falls into the at risk category, are the fix options still the same as the later engines that are included in the class action? Thanks

I'm surprised that your VIN isn't included in the class action suit. The 996 3.4 and 3.6 engines are susceptible to the issue. I think it's still a good idea to have your IMS bearing changed when you do your clutch.

According to the details for the class ours was built about two months before the earliest included VIN. I'm all for replacing it proactively if needed, but I want to know that it is needed (or at least smart) and also that I'm getting the correct fix before spending a bunch of money to tear it down only to have the wrong part.

If I was in your shoes, I would replace the IMS bearing with the new clutch within the next 10k miles. Your motor is prone to IMS bearing failure.

If your car has done over 50,000 then its a safe bet that your ims is going to be ok. Apparently they fail at lower mileage. After saying that, if you are looking for peace of mind and you can get it by changing the one that's in the engine, then simply get the job done at the next clutch change. For further peace of mind there are lots of other things that need to be replaced under "preventative" maintenance according to other users of this board. I BTW have peace of mind with the original one in a 99 engine at 66000 miles on the clock. On the other hand, I have changed lots of other things as preventative maintenance work over the past 2 and a half years. The 996 has certainly made me into a DIY man (to a point). Most times its best to leave things running if they are in fact running and only change it when it fails. But you have the option to change it when the clutch is being changed so get it done for YOUR peace of mind plus anything else you can't manage as a DIY project.

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You are in the same boat that I am. My 2001 is not on the "bad" list and has almost 80,00 miles and is running good. Why replace it at your expense since you are excluded from the lawsuit? If you read the list not 100% of all 996's are going to have an IMS problem. Not true....if he was on the bad list then true. Why continue to pass on bad advice?

Just change the bearing. The cost - if done with a clutch or RMS repair - is no more than 924/944/968 owners spend on timing belts every 40K.

And there are other choices too: - IMS Guardian (warning system) - IMS Guardian Jr (warning system) - the Solution (ceramic bearing and oiler) - DOF (bearing and oiler) and some "invented by the Porsche owner" solutions.

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I did read the list. And you are correct; not all 996s are going to have an IMS problem. Mine didn't. I replaced my IMSB as a preventative measure with over 120K miles on the odometer. On thing is certain though - 100% of 996s have an IMS bearing that can fail. It doesn't matter if they aren't on the list. If technology exists to reduce the risk of a failure, which it does, then you're foolish not to take advantage of that technology. I'm not suggesting that it's an emergency that needs to be addressed immediately, but it should be changed when convenient (such as during a clutch replacement).

Agree with Dennis. Simply change the bearing when you do your clutch as there is no reason to accept the risk given the low cost of replacing the bearing during a clutch replacement. I think we would all like to believe that there is some rhyme and reason that would allow us to predict whether or not our individual car is prone to failure; yet I believe that if there is any rhyme or reason, we will never be aware of it. I have a 2004 C2 that I purchased as a CPO car in 2007. I changed the bearing at 75K miles during a clutch replacement, original bearing seemed fine and it turns out that the VIN is on the list but since I had the bearing replaced I am now exempt from any future claim under the class action. I also have a 2004 C4S and the engine went at 37K miles, before the class action settlement, and the VIN is also on the list. Same owner, same driving style, same meticulous service routine, only variable is the mileage. Yet I did put over 14k miles on the C4S before the engine went. And oh, engine oil analysis on both cars, with oil changes at 5k miles, always looked good.

why is no one offering the usual advice? PANIC!!! just don't drive it in the rain and it will be fine

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Speaking of which...where has Krazy K been?

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Yeah, you stole KK's line.

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Thanks everyone, but this has turned into yet another opinion thread which is not helpful. I'm looking for actual details here so I can make the appropriate judgement. Please understand that if the engine died tomorrow, we'd put a new engine in it. This isn't about cutting corners or trying to save some money, it's about doing the correct thing (which includes not messing with something that doesn't need to be messed with). I understand that even if my IMSB is at risk, after 13 years and 70k it's generally accepted that it's probably fine (thus no panic and tear into it if not otherwise needed). I also know that it's not 100% risk free, so change it when we're in there. I thought the earliest engines (99s? early 00s?) had a different IMSB that wasn't susceptible to the failure (or at least not as much). Is this not the case? If my understanding is correct (different IMSB in the early years), does anyone have any hard facts about when the change occurred? I agree that being on that list or not is not a definitive judgement if you are safe or not. Their reasoning for which cars are included is at least as much due to with the lawyers as it was the Techs. It does, however, give me enough pause to question and verify my understanding of the whole issue.

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Well, you're dealing with a bearing (wear part) that has 70k miles and is prone to failure. Generally I am not one to suggest replacing perfectly good parts unless they are very cheap. However, when it comes to a part that's performance controls the fate of your engine and has a reputation for failing, it's worth spending the extra money and replacing that part (OEM or aftermarket) while you have the engine/trans separated. Do I think it's worth replacing the IMS bearing on its own as a precaution if the engine/trans doesn't have to come apart, no. Because more cars not on the list have had IMS bearing failures. My '99 original engine fell victim to it. That list isn't the tell all of affected cars, just cars that are the end product of the law suit.

I appreciate your concerns gnat. Here are the facts: - All new M96 engines have an intermediate shaft bearing - The early M96 engines utilized a double-row bearing, while the later designs used a single-row bearing - There are documented cases of both bearing designs failing - There are documented cases of high-mileage cars with their original bearing (no failure) Beyond these facts, everything else is speculation as to whether you are at more or less risk than any other owner of a 996. Some people say the early cars have more failures. Some people say the later cars have more failures. Some low-mileage cars fail. Some high-mileage cars fail. Some cars never see the failure, despite being in what many consider "high risk" situations. There's simply no way to predict it. Based on the facts above, you have a few choices: - Leave the original bearing as it is. - Proactively change your bearing to a ceramic bearing. While this is no guarantee of protection from future failure, it certainly seems to reduce the risk. - Proactively change your bearing to an OE metal bearing. Some have done this. It's nothing more than replacing a wear item in the engine with a fresh part. - Install the IMS Solution from LN engineering that eliminates the original intermediate shaft bearing. I don't think there's really a right or wrong answer here. You simply need to understand the risk/reward of each choice and go with the choice that makes you happy. I believe that the vast majority of 996 owners have never heard of an IMS bearing, and have never done anything about it. The vast majority of them will never experience an issue.

Q. So is our engine still prone (using the term loosely) to an IMS failure? A. Yes. Q. Are the fix options still the same as the later engines that are included in the class action? A. Your options include: 1) If you have a dual-row IMS bearing, you can replace it with a dual-row IMS bearing. 2) If you have a single-row IMS bearing, you can replace it with a single-row bearing or replace it with the IMS solution. 3) You have the option of installing the IMS Guardian and worry about which route to take if/when a problem develops. 4) You have the option of doing nothing.

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Thanks. This is the type of info I was looking for. It sounds like (as I believed was possible) my understanding of the single row vs double row change having an impact on the issue is incorrect. That's the real problem here. There is a lot of panic and complaining about the issue, but very few (relative to the production numbers) verified failures. The result is that it's hard to find anything except for the sites offering solutions or the people wringing their hands about the issue. In the end if the real answer is that it should just be considered a wear item that should be changed with your clutch, I'm good with that.

Just to echo what has been said. It is a regular roller bearing. Some obviously fail more than others (dual row vs single row 996 vs single row unservicable 997). All roller bearings wear out eventually. Replacing it while the clutch is out is not a lot of extra labor and putting the LN bearing in will help your resale. I wouldn't go Krazy and immediately yank the transmission but if you have a clutch replacement looming....why not? I would expect being able to say it has the LN ceramic bearing is probably 1k in resale value.

That was my approach. I had my bearing changed to a ceramic bearing on my first clutch change, which was at just over 120K miles. According to my mechanic, the original bearing was showing no signs of impending failure.

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I see what you did there...

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Your frustration is warranted. There aren't many facts and Volkswagen AG or Audi AG or whomever is responsible wants to just let the 996 issues die with time. Porsche sales are up, the 50th anniversary is here, and non 996 values are on the rise. Who gives a flying leap about us? Only us. This lawsuit was only aimed at the group who brought it forward. It isn't possible to read into any implications about those vehicles excluded from the suit. The other issue is that the fail rates are low and preventative solutions are not cost inhibitive. The entire issue is more inconvenient and frustrating than a true reason to be overly concerned with a catastrophic failure. The reward of ownership at these prices still outweighs the risk. My thesis is that very soon the IMS fail rates will be less than 1% as solutions become more common, inexpensive, and a part of 996 routine preventative maintenance schedules. This is an iconic car that has been given a unfair rap with these issues and the Boxter front end. Even the nonsense about the head lights is intellectually dishonest and I salivate at the chance to debate a so called "purist" a$$hats about what makes a 911 a real 911. Most people who don't like the "scrambled egg" lights are sheep who were told not to like them. I will never change mine but to each his own. So in the absence of scientific data and the unlikely possibility that any real data will ever be sampled correctly, one has the following choices: 1. Let it ride and accept the unlikely scenario that you will crap out with a bad IMS 2. Wait until it is time for a clutch replacement and do both 3. Find a lawyer willing to take on a new class action lawsuit (Pro Bono) to include every 996 ever manufactured I personally purchased a costly power train warranty to get me to 50k miles and my clutch replacement. $166 a month for peace of mind. Given the extreme low purchase price of my car, this warranty is still a great value. I actually hope mine fails in the next two years or 20k miles so that Santa Claus will bring me a new engine. If not, I plan to do both the clutch and IMS replacement and roll the dice that time will heal the 996 and values will come back up. Heck, whatever else do I have to do with my spare time?

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I doubt this will ever become a 2nd owner car. She keeps bringing up a 991 C4S, but as soon as I point out that she'd have to give up the 996 she drops the subject Either it will go to the junkyard as a total wreck or she'll be buried with it (or maybe both I suppose...). She might not love it more than our son, but I have no doubts about where I stand in the pecking order...

Sounds like she is more priceless than a bullet proof M96 engine. You lucky guy.

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No the lucky part was this: Me: The Escape isn't big enough to travel with the new baby and 3 dogs, we need to replace it. Me: ...trying to stay in the $30k range... Her: Why don't you look at the Cayenne Me: ...really loves my new P!g even though it required raising my already raised budget... Nothing like a wife that is more into cars than you are Edit: And I figure the Cayenne can always bring the 996 home should it find a spot of road where it feels the engine belongs better than under the bonnet

I personally would be loath to drop a high mileage motor in order to stick some after market part in it. Second rule of engineering ... "If it aint broke, don't fix it!" Given the ever falling prices of replacement motors, I consider Ebay to be my insurance policy. And that insurance policy covers ACTUAL engine failures, not just imaginary ones

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Horse Pucky! You are running scared and not thinking this through. Page 11 of the main IMS thread....

To the OP, heres the link to some more info. Some very informative, some genuis, and some total crap. https://rennlist.com/forums/996-foru...-and-pics.html To all other concerned fellow 996 NA owners, what do you guys think about JR's alternative theory for IMSB failure. Im referring to the IMSB failure being linked to an improperly machined bore line in the block? Maybe we have all been blaming the cheap sealed bearing when the real culprit is poor machine work by Porsche? Maybe just another factor to consider? Does Porsche check the bore alignment (along with other things) when cores are returned to Germany?

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It is an interesting theory but I do not think this can explain the failures. The crankshafts of some engines were found to have shifted (the crankshaft "cradle" shifted) and often (most of the time) the first symptom was a leaking RMS. A new RMS didn't remain oil tight long. Often the engine just failed. Early on ( circa mid 2002 ) it was SOP to check the position of the crankshaft's RMS journal prior to replacing the RMS. If the crankshaft position was out of spec the engine was replaced. My thinking is mis-alignment would have the bearing failing early rather than later. Also, I talked to a senior Porsche tech who was in the middle of rebuilding a car's engine (under warranty as per Porsche factory) that had experienced a IMSB failure but the driver shut off the engine in time and resisted the urge to try to restart the engine and I asked him a lot of questions. He said that for the engine to be an acceptable rebuild candidate Porsche required certain checks. I won't list them but there was no mentioned made of checking the position of the IMS bearing bore relative to anything else. He did offer the observation the car was a classic "SF" car. I asked what he meant by this. He replied to the effect the car got driven 5 miles to the office. 1 or 2 miles to a restaurant at lunch time -- to and from the restaurant -- and 5 miles back home at the end of the day. This suggested to me short trips with resulting oil contamination and subsequent acid build up in the oil resulted in a compromised seal. This by itself is bad enough but maybe not fatal. However the acid that builds up over time attacks the bearing ***** and races and their surface integrity is paramount to their proper function. Also, the acid attacks the bearing cage material, the cage which is critical to maintaining proper ball spacing. My take away was usage played a role coupled with servicing that didn't mitigate the effects of the usage. A few failures could be attributed to just a defective bearing. It happens. Last, I would think if a bore was out of position this would be obvious when the engine was being assembled. No one who has done the IMSB upgrade or had it done and to engines which had a bearing that looked on its way to failure has ever reported any issues getting the replacement bearing back in the engine. Also, the replacement bearing would I think be just as affected by the OE bearing and its life be short too.

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I think it's a convenient way for him to explain the numerous failures of his own(LNE) bearing...

I pulled the ims out of my '02 at 63k since I had bad rms leak anyway. Did rms, aos and oil cooler o-rings .. So cost of doing ims at that point was basically the cost of the part. My old bearing was fine btw. To me this was like taking out $650 insurance policy on $20k engine ... With 3.4 engine there are plenty of other things that could fail before 100k miles and chances are that with regular oil changes you would be fine at this point, but if you need to do clutch anyway why not do it because although the failure rate might be exaggerated on boards like this - it is a weak point in the design - and relatively small insurance cost to replace at that point ...

I think Dennis C nailed it on page 2 and that gnat has picked up on that advice. It's insurance plain and simple. The IMSB represents a risk which is difficult to quantify, and there exist options to mitigate that risk. Frankly the cost of replacing the IMSB is so low I just can't understand why a person wouldn't do so. I suppose someone could believe that they are actually increasing their risk by replacing the IMSB, but golly in that case I'd be thinking about a Toyota or something. In my case (FWIW) I left my bearing alone when I changed my clutch because my engine was factory replaced in 2005 with the new style "big" bearing equipped engine. There's no way to change it without splitting the case. I sleep well at night because so far I have only heard of *one* failure with this type of bearing. If you know of more, please let me know.

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Hello Macster, that was a good post. I agree that this kind of usage is definitely a risk factor. It may not fully explain all failures, but it must be a contributory element. One question though... I can't figure out what "SF" stands for in this context?

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Sexy Female Some Fokker Stinky Finger Silly Fairy Suave Fellow San Francisco Saint Francis Summer Farfegnugen

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Oh, sorry. SF in the context of my earlier post and what the tech said stands for San Francisco.

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"Silly fairy" - same thing

Thanks!! (Although I liked the idea of silly fairy too...)

I've got 1,000 miles on my '04 since getting it in Aug. The total mileage is 64k. I was a "bearing hawk" originally. Now, I think I'll wait until the clutch needs replacing to do the IMS solution or bearing replacement. I've got a 2-year/24k mi. warranty so I'll sleep a bit better but, after all, we're not driving Hondas and high-strung machines break occasionally. Sorry to be blase but... TC

I was about to drop mine off this weekend (2001 26k miles) but thinking now I may get a 3yr 36k extended warranty http://www.aaautowarranty.com/nasc-silver.asp instead for $2000 and replace the ims at a later time with the clutch... hmmm... Decisions...

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+1 on the warranty

Warranty over IMS swap is a no-brainer.

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Yeah ... Think what else can go wrong