Who still has their original IMSB? And why?

Fifteen months ago when I purchased my 2002 Targa I'd heard of "issues" with the 996 motor but wasn't overly concerned. In the coming months after perusing these forums I developed a paranoia that had me waiting for my engine to detonate at any second. Originally I planned on having the $2500 clutch and upgraded bearing done ASAP. But a very expensive unforeseen repair on my BMW made me put the bearing upgrade on hold until I could raise sufficient funds. Then getting run over by a car while cycling put me even further into the hole. Finally back to work after 6 months things may return to normal. The last few months I've calmed down. At 71k miles my car isn't one of those seldom driven garage queens, oil changes come every 3k miles. Upon examining my filter not one fleck of anything shiny is to be found. And my clutch isn't slipping. When I have the funds to do the clutch and bearing I'll do it. It just doesn't keep me up nights worrying anymore.

I would say if your checking your filter every 3 k you should see the signs early enough to stop driving it and have it done, they say the failure rate is 5% on single row bearings and 1 % on the earlier dual row , there is the option of a magnetic drain plug from LN Engineering or the ims guardian which replaces the drain plug with a sensor that sets of a warning light and buzzer on your dash, also fits into one of the buttons on your centre console so quite neat!

112,000 miles on my original dual row bearing.

There is a lot of internet hype that has added fuel to the fire. Yes, there are plenty of stories about the impending failure BUT, some owners haven't driven their garage queens enough, some have followed the Porsche oil/filter change (12k miles or so), and others have theirs replaced immediately after taking ownership of the 996/997. I check my filter and change the oil once a year at only 4k miles driven, and have 68k miles on my C2. Last oil change I found no particles of any kind in my filter element or the magnetic drain plug. Some other Rennlist 996 owners share my belief that our IMS are fine, others have to upgrade at once to the many offerings available as soon as they purchase a used 911. I think you have to make your own decision that you are comfortable with regarding this repair. Read as many magazines out there that have written numerous articles and that may help you decide the best choice for you. hope you've recovered from your bike accident.

I do. It's on my desk :/

139,000 miles on original 1999 996 IMSB. Why still original? No reason to replace it. There are just as many other engine components that fail but are not hyped (like lifters or chains or tensioners or... the list goes on and on). Last month I had to rebuild my Boxster engine with 136,000 miles and 89 track days on it. The IMSB was in perfectly good shape (engine had a failing lifter). What I really needed was a "Hydraulic Lifter Guardian"!

I had my IMSB replaced as a preventative measure when my original clutch was replaced at roughly 120K miles. The original bearing did not show any signs of impending failure.

Even if you had the $24k to replace the engine, good luck finding one. And good luck selling your car if you haven't had it done. Thank the internet for that one. I look at it as regular maintenance. My car hasn't cost me a dime to repair, so I'm not that upset about doing it. If it comes back next week that it was in fine condition, no biggie.

I think my car still has the original IMSB and I don't have a history specifically on the IMSB since I bought it from a used car dealer - although a very reputable one. Before I bought it however, I checked with the Porsche dealership where the car was purchased and serviced for its first 67K miles and no major issues in the car history - alternator was changed once. However, the following 10K miles is a bit hazy. Anyway, as a precaution, I bought extended warranty for $2500 to protect me in the mean time ($2500 now or $20K later), but I plan to take it in soon to have the IMSB upgraded to have a piece of mind. I just did a DIY oil change and checked the filter and it was clean. I do agree that preventive maintenance beats repair almost every time. Plus, if the engine goes, where am I going to find an engine?! No, I won't take chances.

I have the durametric tool. Is there a way to monitor impending IMS wear using the tool?

My 02 Boxster has its original IMSB. 280K miles and counting. Why? Because it is bullet proof.

140k plus miles 15,000 mile oil changes original IMS bearing running like a champ

65k miles on original and i dont plan on spending $800 on a stupid bearing just because people on the internet whos you know whats are the size of that bearing complain that its the weakest part in the engine. If my engine kaputs because of that i will just set it on fire and ditch it. Rubik youre like 3 miles away from me

Bought last August with 63k mi. Oil change at 5k. No sparkles in the filter. At 73k now. Due for another oil change and 75k service. Indy says the clutch may last till 80k. DD when I'm home (12 days/mo. +/-) but no tracking. Original single row which will be replaced with the clutch. TC

Quotes source post: 11486813

280k mikes? Wow! What's the trick?

Hooray! A 4th of July IMSB thread!

1999 C2 72000 miles original double row IMSB. Motul 100 Oil changed at 5000. No debris in filters. Don't have the magnetic drain plug anyway. Same clutch since I got the car at 45000 miles 3 years ago. The reason why I never worry is "It's a Porsche, there is no Substitute".

105,000 miles on original IMSB and no intention of changing it out. Car runs like a champ! Pete

Sent mine back to LNE - part of the warranty.

98,000 miles. I believe there was a thread where a Porsche dealer mechanic stated he had done many many IMSB jobs, and said once you reach 60,000 miles, the probability of failure is almost nonexistent, and I am paraphrasing, but that was the general idea. 2002 Turbo - Basalt Black Metallic / 2003 Carrera 4S - Speed Yellow / 1955 356 Continental 1500 - Rust Red

Quotes source post: 11487051

Avoid the internet. Drive the car.

Quotes source post: 11487603

+1/2 ... I'd rather read everything, decide how worried I really need to be, and then just drive the damn car. Seriously, I think you described the anxiety curve for a lot of us ... starting with "what's an IMS?" to "OhmiGod it's a friggin' time bomb!" to "guess I'll get that done when I need a new clutch." I negotiated my IMSB replacement with the purchase of the car, since it needed a new clutch. Otherwise, I think I'd just have waited until the clutch went.

Bottom line, can it happen, yes. Does that mean it will happen, no. Decide what makes YOU feel better at night and don't worry about anyone else.

MY '03 original single row here at 61k. Oil change, UOA and filter inspection every 4-5k. If you are worried, just change it out with a clutch job.

lol Another IMSB thread. In my job, I mitigate risk at every opportunity- so I changed mine with the clutch/AOS/RMS job. Turns out its a double row version...so that's awesome.

Quotes source post: 11487754

My Boxster's clutch is original at 281K miles. You could be waiting a long time.

Quotes source post: 11487916

What do you do for work?

Quotes source post: 11488200

I R an airline captain. ( but I watch a lot of Jason Bourne movies on weekends) Derp- lol

131k with no signs of failure!

Early-build '05 997 with small single-row IMSB. Bought it with 20K on it, clutch pedal was quite stiff, so at 32K I decided to do it and get the LN bearing at the same time. Original bearing was perfect, seals intact, grease inside. Over 20K on the LN bearing so far with no issues. I also have a B2B warranty for another 2 1/2 years. But I agree the internet hype can make you crazy. The guys selling the DOF system claim the LN is not a solution, and even LN says the single-row retrofit isn't a solution either and should be replaced at intervals. But there comes a point when you have to say "enough". If there is a 92% probability the OEM bearing will go the life of the engine without even removing the seals, then my sensibility tells me the open ceramic LN bearing which withstands suboptimal lubrication should have a much higher probability of surviving to the bitter end. I can live with that.

99 duel row, 80k miles

2003 Carrera 2, 45k miles, original IMS. Transmission was dropped to fix RMS but the IMS flange showed no sign of leak AND most importantly I am still under extended warranty so I had to keep the IMS if I wanted to keep it intact.

With the failure rate poll right at 10% and most experts saying its a wear item, why not change it at every clutch job? Its too cheap and easy not to.

Quotes source post: 11488346

I would agree, but the single-row LN bearing (which most of us have who had it done prior to this year) is recommended for a 4 years/50,000 mile service interval. Maybe if one tracks the car a lot and/or is really rough on clutches it might need replacing that often, but for most of us I don't think it would. So it becomes a case of the tail wagging the dog.

With the number of 996's built and only 5% or hell even 10% failure rate your chances of getting hit by a bus walking in LA streets is alot more. So there are bigger problems to keep me up at nights i dont worry a single bit.

Quotes source post: 11488346

... and those would be the people selling the replacements?

04 C4S Cab, original IMSB, 77k miles. Replaced the clutch in 2012 at 69k miles, replaced RMS and IMS flange but car was under warranty at the time so had to keep the original IMSB. Warranty expired past February. Considered ordering a replacement IMSB but I am afraid of the installation process. There aren't experienced techs in IMSB replacement in Portugal. So the "cure" could be more risky than taking my chances with the original IMSB. IMSB failure did happen to 2/3 early 996 3.4L here in Portugal but never heard about a failure in a 996 3.6L around here (not even in portuguese Porsche forums, or at the Lisbon OPC where a good friend of mine works or the Portuguese Porsche Club). Most 996 engine failures around here are due to crank main bearings failures (know of 7/8 cases). CS

Quotes source post: 11488947

Agree. These sellers of replacement bearings have made quite an industry out of the paranoid masses.

Quotes source post: 11488346

why on earth would anyone believe this is statistically correct? Don't you think people with the IMSB problem search the internet and find this site looking for answers and fill out the poll? 2002 Turbo - Basalt Black Metallic / 2003 Carrera 4S - Speed Yellow / 1955 356 Continental 1500 - Rust Red

Quotes source post: 11488908

This... '99 986, 88k miles on original dual row. I won't change it because I'm not a hypochondriac. Maybe if I ever do the clutch, but that's a big maybe. As I've said before, based on observation alone, it is much more likely that you will total your car in a wreck than have an IMSB fail. Just drive the damn thing

97.2% of statistics on the internet are made up... The odds of being hit and killed by a bus are one in thirteen million...just SLIGHTLY lower than the 1-in-20 to 1-in-10 chance of having a 996 in which the intermediate shaft bearing fails. I don't worry a single bit either - I replaced the bearing. I honestly don't understand how people shrug this one off - the risk vs. reward (a few hundred bucks spent vs. $10K plus saved) makes this a straightforward decision for me. I agree that spending money out of paranoia is stupid. The settlement agreement (or some of the supporting documentation, I don't recall which) included statistics from Porsche estimating the number of failures for single-row bearings up to 10%, moving this issue out of the realm of paranoia into the realm of fact. Failing to act because one chooses to categorize a known issue as paranoia is just as irresponsible as spending money on something without performing the due diligence to know whether it's warranted. You realize that the number of 996's produced is irrelevant for this statistic, right? If you prefer not to update the bearing, that's fine - but suggesting that the odds are lower than they really are isn't very responsible when you're posting that opinion in a forum used by many, many people as a technical resource.

Quotes source posts: 11489688, 11489688

The annual odds of having a "reportable" accident is approximately 5.5% (annualized). NHTSA records show that one out of every seven accidents results in a total loss. So, the odds of totaling your car in any given year are ROUGHLY 0.78%. Put differently, a 996 is about 13 times more likely to suffer an IMSB failure than you are to total your car next year. I appreciate that folks are trying to reduce 996-related hysteria, but just making sh*t up isn't the way to go about it. I'm not a hypochondriac either, but if my MD told me I had a 10% chance of having a fatal heart attack next year, I'd start eating baby aspirin for breakfast.

The ego is a funny thing. People will defend their choices to the death You and I both. I respect your choice, but I don't agree with it and will defend mine. As I very clearly said, my statement was based on observation. I see many more posts about wrecked M96 cars than I do about IMS failures. I'm just not one of those people that let fear control my decision making process and even if I did, I don't buy into the hype, so I'm not scared I might die of a violently explosive fart tomorrow, but I'm not going to lose any sleep over that possibility tonight.

Heh. Noted. As far as death - sure, I'm OK that I spent the money, but this ain't the hill I'm dying on. People can do whatever they want vis-a-vis their own car - I just don't like seeing "statistics" getting thrown around when they're either (a) bogus or (b) unrelated. I know that my 996 has a 100% chance of dying someday, and replacing the IMS bearing does nothing to change that. I just elected to treat an area that's known to be a problem so I can keep it around long enough to (hopefully) have it die from something else. I didn't bother with the IMSB upgrade on my Boxster, as frankly I didn't care about it as much as I do my 911. Even if a full 10% of M96-powered cars really do suffer from IMSB-related issues, the other 90% have to die somehow. Personally, I'd prefer to have my car die in a ditch - backwards, on fire - than from something mundane like a bearing.

Quotes source post: 11489885

Well said. I'm not at all saying that my viewpoint is any more correct than anyone else's, but simply stating my view and the reasons for it. Now it's going to bite me in the ****...I can feel it, haha! If my engine grenades, I've got no one else to blame

"I appreciate that folks are trying to reduce 996-related hysteria, but just making sh*t up isn't the way to go about it." I started this thread not to suggest the IMSB wasn't an issue but that taken on a case by case basis I personally in my case don't think doing it immediately was absolutely necessary. With oil changes every 3k and examining my filter I'll monitor it closely. I have every intention of changing the bearing in the very near future. Just not today.

Just like to say IF and its a big IF I put my car up for sale at my price, I will stick at my price. If the prospective purchaser complains because I have the original IMSB in the car, and he wants to haggle, then I will kick him in the **** and send him on his way to look for another 996 that has had the IMSB done. Just saying. But 'meaning' my statement. Clutch or not being changed, my IMSB stays original. There is NO PROOF that the replacement IMSB are Bullet proof. I would like to know the highest milage done from our posters since the replacement of an IMSB.

Quotes source post: 11490287

Are there any actual reports of the LN IMSB failing? This is pure curiosity as I don't care whether people replace their's or not.

I have no reason to doubt LN when they say a few single rows have failed. Cars with the single row outnumber the double rows by a large number. And the small bearing's lower load rating probably leaves less to spare if it gets compromised. That said, with 92% of the OEM bearings not failing, and the LN being better suited to minimal lubricatiion, my intuition says to suspect ham-fisted installation, and/or placement in cars whose original bearings have already deposited swarf in the crackcase as plausible factors in at least a portion if not the majority of those that have failed.

Quotes source post: 11490522

That seems like a reasonable assessment. I have also noticed dealers installing who are not on their site's approved list.

Guys, perhaps we are approaching this incorrectly. Maybe the right question to ask is: How many people have upgraded to the LN IMSB including number of miles on the new bearing and how many failures after upgrade? This is the poll numbers I want to see!

Quotes source post: 11490727

This is a moot point if a "certified" installer didn't do the work and also didn't perform a pre-inspection as this has to be done and pass before a LN IMSB retrofit can be carried out according to Jake. Plus the older versions of the bearing didn't have LN stamping on it making it hard to prove whether it's genuine LN bearing or not. Then pre-"faultless" installation tool, you could always blame it on installation error. Oh and don't forget that now the IMSB has a service interval and those numbers only apply if you are using JG DT40 oil and sticking to their OCI'S. Also forget about tracking it. Lot of caveats and asterisks is the bottom line to make the kind if poll you're suggesting pretty much worthless, playing devil's advocate.

Alpine003, I completely understand your point and yes - absolutely - there are a lot of variables. But based on the IMS poll numbers on Rennlist, 9.x% have experienced failures. If after upgrade that number changes to - for the sake of argument - 3%, then there is no argument.

People shouldnt take my or anybody elses' opinion as a technical resource. Im not telling anybody to do it or not. If its gona help you sleep better then thats your choice, and for the price of the work its not worth loosing sleep over. I sleep like a baby with the original bearing in there. Just sayin that it doesnt bother me a bit.

For the record, I had never even heard of an IMSB before I bought my car, so it had zero influence on what I paid for the car or on my decision to buy it. I suspect there are many similar buyers out there. But, I did replace it with the LN bearing, just for fun, thanks to RL forums. My Mastercard thanks you all.

Quotes source post: 11490766

I guess I should've just said all polls like this, especially on Rennlist is utter crap and hold no kind of merit or validity IMO. I don't expect the kind of poll you want to do will either. My $.02 Also remember that IMS is the scapegoat whenever something fails. In most of these cases, people have assumed the IMS was at fault without properly tearing it down and diagnosing the part. Most dealers will just replace the motor without ever tearing into the original motor and doing a proper diagnosis. So in reality, even that 10% figure us even further skewed. I think you know where I'm going with this...

Haven't read the thread as I have been busy driving my car. Can I safely assume that the IMSB issue has been resolved by this thread? Awesome.

DTM: Here's a summary: Some people: I replaced the bearing. Other people: Pff. Stupid. So endeth the summary.

Quotes source post: 11490287

The replacement bearings are not advertised as being bullet proof - you're looking for proof to support an assertion that nobody is making. Belligerence doesn't really affect the bearing's necessity or longevity...

I think the good news on the 996 front is that the M96 paranoia/mania/silliness has blown itself out. These motors, like pretty much all Porsche powerplants from any era, have their problems. But they are also compact, light and very powerful as well as tractable and dependable when compared to other 300 HP sports car motors. The market is reflecting this attitude adjustment and 996 prices are stabilizing, pulled upward by the higher prices being commanded by newer Carreras. I chose to update my bearing but I also have modified other parts of the motor. I like the fact that 996s will likely never be "collectible" since it allows me to guiltlessly mod my way to nirvana. Make my burnout extra smoky please.

Quotes source post: 11491617

True ! Makes for guilt free high mileage..drove it like you stole it fun.

When my 2000 Boaster S turned 142k I had to do the trans for 2nd gear pop-out. I left the IMSB alone; the car now has 170k. No worries, it's a car I'll own until I cannot own a car. When the clutch went in my 1999 C4, the car had 72,000 miles. I balked and replaced the IMSB. It was perfect. Part of me wishes I had let it be, but I learned a lot by doing the job myself, and if I had to sell the car, the New LN bearing would be part of the ad.

"...so endeth the summary" LOL Outstanding

not replaced mine, 55k miles 99 double row.

A 99 with 55k is a garage queen.

04 with 41K mi

2003 with 97k and a pile of autox events. No flakes in the oil, will replace or inspect when the original clutch finally gives up.

I don't know why I found it interesting that no one mentioned they don't worry about their IMSB because they have the Guardian installed. Which is my answer. A couple of years and oil changes later and I only find the same very slight film of grey on the magnets. So I don't worry about the IMSB or any other metal wear at this point at 53k miles. I'll worry about replacing it when it's clutch time.

01 c2 tip, 62K, no particles in filter, cam deviation within tolerance and steady, DD last 4 years. Don't think DDs get sick like recreation cars. Never think about IMSB except when on forums.

I still have mine I use it as a paper weight

Just replaced mine, gave in to the hysteria. Had 33,000 miles on my 2002 C4S. Replaced it myself with a Pelican kit. The original bearing was fine, but had a cup of oil in the IMS tube, that is now on my garage floor!

Original up to 88,000.. Replaced with LN while doing clutch & RMS. Did it need it? ...No... Stock bearing was perfect, but to me $600 on a part that can have issues, is cheap insurance.

Quotes source post: 11562737

I debated whether to even post this question, since I'm pretty sure it's going to be misinterpreted, but I'm going to give it a shot anyway. When the Guardian goes off, it's an indication that you now have metal in your oil pan and you need to shut the car off. However, once there's enough metal in the oilpan to jump the electrodes in the Guardian plug, isn't it also true that you likely have metal everywhere you have oil in the motor? My assumption based on other posts is that just replacing the bearing at the point you already have bearing debris throughout the motor is stupid, since you can't ensure that you won't be pumping metal fragments through the replacement bearing. This seemingly makes the Guardian an indicator that it is now time to flatbed your car somewhere to have the engine torn down, cleaned, and reassembled - so I'm unclear on how the Guardian is better than getting on a maintenance schedule that includes replacing the bearing at appropriate intervals...

Quotes source post: 11568560

If the Guardian is sensitive enough to warn when fine particles are emitted from the IMS and the operator shuts the car down before larger bits emerge, the Guardian could save the engine. If the first bits off the IMS are large chunks there is no suitable warning.

For what it's worth, if I were in the market for an m96/m97 powered car I wouldn't touch one with an after-market IMS bearing. For much the same reason I would avoid a car with any significant engine mods (to include air-intakes, exhaust, cams, lifters, ECM, etc.) I'm a purest and such cars set of my probably-has-been-hooned sensor. For you folks that go the after-market bearing route, do you feel the need to continue to replace the bearing every 30k miles as has been recommended? Given the price of 3rd party warranties, or the ever falling prices of salvage motors, would that route not provide a lower cost option? Given the number of ways a performance motor can be destroyed it seems like this particular modification is akin to purchasing an insurance policy that only pays if your car catches leukemia on a tuesday. To answer the OP's question, I'm currently running 2 m96 machines, a 2.5L @ 140k miles and a 3.4L @ 94k miles, both original bearings for the reasons stated above.

I bought my latest 2000 996 3.4 with 130k miles and a leaky RMS for a song. It was a local car with a stack of dealer receipts from new. I took it to the dealer, where they did the RMS, IMS, and some odds and ends for $1,500. They came with a two year, unlimited mileage warranty.

Quotes source post: 11569495

Hope this doesn't come across like I'm raining on your parade but at that price that IMS job did not involve an IMSB upgrade. At that price and with the other things you had done I dare say it was the IMS end flange and bolts that were replaced, along with RMS and some odds and ends.

Quotes source post: 11569749

No problem. I figured as much. I was buying the warranty. If it grenades, I know Porsche's good for the labor of an engine pull, plus likely a few grand prorated credit towards a shiny new engine. I'll still be into the car for less than a new WRX.

Quotes source post: 11568560

No, not misinterpreted at all. As the other poster mentioned, it should alarm well before damaging amounts of metal occur, and well before the bearing grenades, which you have no chance at all of knowing without it.. Jakes tests made that clear as to its usefulness. In addition, which I'm surprised you didn't catch, since I have the spin on filter adapter, with a Mobil 1 full flow, no bypass filter on it, which filters far smaller particles than the OEM, no particles big enough for the filter to stop would ever enter the engine anyway, just pass through the primary oil pump. It's a one way trip to the pan & filter with a no bypass unit. What more can you do?

92K miles, still original.

92k Miles, still original.

2002 C4S Tip. 102K Miles. Original IMS, no issues....

Quotes source post: 11486813

That is very impressive! Would you please share what kind of oil you are using and often do you change it. Any other advise to extend the life of our engines would be appreciated as well. Thank you!

93k original IMS. Noticed small specs of grey debris in oil filter from last oil change.