Looking for new theories on IMS bearing failure. Several thoughts...

The auto industry is filled with examples of bad designs that have had serious failures. Ford, GM, Audi, Toyota, Jag...no one has been perfect and all have made sins of ommission or commission. And there are examples of how it is sometimes impossible to make a bad design into a good car...such as the Maserati Biturbos as sold in the US. Porsche however has a status and reputation in the industry that is hard to equal. Things break. Nothing is perfect. But I find it hard to imagine that Porsche has been intentionally, for many years now, negligent in this IMS bearing issue. 1. The low volume and random nature of the IMS bearing failures makes it hard to point at design flaws. Especially when the design fix would have been so easy and when the turbo engines seem free of this flaw or other flaws like it. 2. The engines are hand assembled...has anyone ever traced the failures back to the people who assembled the specific engines that failed...to a specific team or group or shift or individual? 3. Assuming that the flaws are not in the design of the bearing or the engine assembly, and assuming that the bearings are not created inhouse but comes from a supplier, one has to wonder if Porsche has vetted their supplier for poor quality control or even disgruntled worker sabatoge? 4. Lastly, the class action suit proves that Porsche is like most companies and that they may have felt it is cheaper to pay for things to go away rather than defend their product in court. That said, has there been any statistical analysis for common threads of service or driving styles or conditions to see if there is a "possible" service or driver factor that stands out in these failures? 5. Since the issue seems restricted to 996s, how has the design changed in the 997 to avoid the problem...and can that change be retrofitted to the earlier cars? Just thoughts for discussion.

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Wow.

Once upon a time there was an IMS containment thread stickied. What a wonderful time that was.

Now that is a new and interesting perspective.

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https://rennlist.com/forums/996-foru...his-first.html The thing I found is one IMS thread is never enough...ppl like to have their OWN IMS thread... OP, not to be hard on you but if you search, there must be like 100's of IMS threads on this site alone and everything you asked has been discussed ad nauseum.

yes there 100s of ims threads...and none of them brought up these points...at least that I could find. So in good faith I am asking these questions and would like to hear replies. As the new owner of a 2003 996 with 39000 miles I have dealt with the issue for now by purchasing a 3 year 36k service contract. That seems like enough protection for the immediate future and it will allow the design to speak for itself. John

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Yes they did. I promise.

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No, the subject of your questions, although maybe not specifically as you asked them, have been covered in the dozens of threads on the subject. And, the IMSB problem is not limited to 996s. It occurred in all M96 engined Porsches including 986 and early 987 Boxsters, 996s and early 997s. It is a design problem. In all seriousness, read the IMS threads. Also check the 986 Forum. Heck, even search other forums on the web. There are lots of questions and very few answers.

1) The M96 was not low-volume (in Porsche terms, at any rate). 3) The flaw was using bearing A for application B. "Sealed" bearings are not permanently sealed - I just replaced the "sealed" bearing in my front-loading washing machine. Once the seal is compromised, the bearing is toast. You'd be amazed at how much the bearing in my washer looked exactly like a chowed IMS bearing. There is no subterfuge, no conspiracy. 4) It's ENORMOUSLY cheaper to replace SOME engines under warranty and SOME under the class-action (as long as they've been in service for less than 10 years) than to replace ALL engines w/ a recall. 5) The issue is not limited to the 996 - the M96 motor was used in the Boxster for years as well. The "fix" for the M97 - to use a bigger, non-removable bearing - didn't fix it. Porsche produced engines with permutations of the IMS bearing we know and love for 11 years.

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You're covered then for the yr/mileage (as long as the the service contract is good. More on that point later). Maybe after the term is up, re-evaluate and just replace it if it keeps you awake at night. In the meantime, install a magnetic drain plug, do oil change every 5k/6 months and inspect oil filter for debris pretty much minimum. Service contract terms need to be read very carefully for exactly what is covered. Some contract says specifically only the engine parts that are lubricated by engine oil are covered (as far as engine coverage goes). Now I can definitely see that the warranty company can argue the IMSB is NOT lubricated by engine oil, well at least not by design...you get my point.

4) Porsche also estimated the failure rate for MkII is ~8% in the class action lawsuit.

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But since it is a slow and rainy afternoon... 1. The Turbo models do not have an IMS. In the non Turbo models it wasn't fixed at the factory since the flaw was not readily known when they were in production. Plus, Porsche was going broke in the early days of the 996 and would not/could not have done anything about the design. For all the 996 haters out there (you will find out why if you do another search), the 996 saved Porsche. 2. The IMS is in all 996 and the early 997's. I am sure Gerhardt who works on the assembly line may have had a few bad days, but it would be difficult to know if it was he or Hans that failed to tighten down that last bolt on the IMS. I suppose either one could have been in a hurry to get to the bathroom after having eaten bad schnitzel, but I doubt there would be records of which autoworker installed each specific IMS. It is also thought that the single row bearing is less robust than the double row, although both have been reported as failing. 3. Your assumption is wrong. IMS failures are a result of IMS bearings that fail. I like your sabotage idea though. Now that IS an IMS discussion I have not heard of before. Maybe Hans and Gerhardt were both disgruntled because they really wanted to work in the brand new Cayenne Assembly Plant, complained and were told they were going to the Boxster Factory if they didn't shut up. 4. As noted ad nauseum in this forum. Yes. Garage Queens and cars that are not driven "Like you stole it", seem to be more susceptible presumably because the engine (and IMS) is not getting lubed properly (I sound like JRosa here). Also, Porsche did recommend oil changes at high mile intervals, but it is generally agreed upon that every 6 months or 5000 miles is a good deterrant to IMS failures. It also gives you the opportunity to cut open your oil filter and look for metal (ferrous only) debris. 5. The early 997's (997.1) had IMS issues because they have an IMS. The 997.2 models avoid the IMS issue completely...because they don't have one. Anyway, Welcome to Rennlist! Do you have a pic of your car?

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True: False: One car is not a valid sampling. Even if the actual failure rate was 25% (and I am not suggesting it is 25%, so everyone can take a breath), your specimen would only have a 25% chance of exhibiting the issue. A single data point is not sufficient for "the design to speak for itself." You may come to the conclusion that we're all a-holes, but waltzing in here with 5 posts spouting off about IMSB conspiracy is going to raise a few hackles...

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Is there a warranty company that anyone uses that will specifically cover this issue?

All the contracts I've read say they cover "all lubricated" or "all internally lubricated" parts of the engine or some such language, without specifiying whether that lubrication is in the form of splash/spray oil or sealed bearing grease. The real issue is what language the contract states in terms of the total amount of payout. Many of them have clauses limiting payouts to the dealer wholesale value of the car, which in the case of at least some 996's would be less than the cost of a new engine.

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Uh oh.... Latest studies show: But just so you don't think we are all complete tools (only most of us), everyone is dog-piling on your questions because it is the most overdiscussed topic in the world. OK, well maybe just the most overdiscussed topic on the 996 forum. Plus many of your assumptions are incorrect, and your questions have already been discussed and answered many, many, (many!) times..

...ad nauseam.

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HAHAHAHA! Love it, especially on a rainy afternoon.

the continuing photo shoot of someones avatar

Somebody shoot me please

I vote for this thread to be turned into a booby thread.

I keep my hopes to high I thought, we were going to close the week without a misplaced IMS thread !!!!!!***** thread if you post a reply non ***** related you like the IMS better than ***** your call!!!

To me, Porsche's refusal to be forthcoming about the IMS reliability problems (data?) and willingness to extend the M96 warranty period accordingly represents the final insult to 996/997/Boxster owners. Porsche chose to fight their customers in the U.S. courts instead. Draw your own conclusions about responsible corporate behavior. relinuca

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Ok you wrangled me back in. The million dollar question lies in what exactly constitutes a "problem"? Does .01% reliability or defect considered a problem or industry avg? The magical number that no one really knows and that everyone speculates on all the time. And I possibly mean no one, not even Zporsche possibly. First off you have idiotic owners that can't maintain their cars, let alone drive them and some find it convenient to cry wolf and conveniently blame it on the IXX automatically. Secondly, it has been confirmed there are many modes of failure which contribute to IXX collateral damage. Third, Porsche just finds it easier to replace motors rather than properly diagnosing them and repairing them. Had they gone this way, the diagnosis could've pointed to other things. And personally, I can't see Porsche doing an thorough autopsy on every motor that's been replaced and sent back to them, and it is this reason why I don't think they even know 100%. My $.03

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Be sure you read the fine print of that service contract to find out just exactly what you have to do to keep in effect and what is covered should the worst happen. Added: I should have read all posts before responding. I see others have advised you to read the fine print. I'll leave this post here to just stress how important this is. Also, be sure you do some research on the company offering the coverage. It is not unknown for a company offering this kind of coverage to not be around when the time comes to file a claim. Also, check with where you will have the car serviced and possibly repaired (should the worst happen) to get a feel for how this company is to deal with. Some companies are pretty easy going, as easy going as any company can be in this line of business. Others strive to avoid paying out anything for any reason. Some techs have told me the claims adjuster will come in and ask a zillion questions about the car, the usage, servicing, etc. seeking of course to find any reason to deny the claim. This is ok as the company is entitled to avoid paying out for fraudulent claims or for claims arising from abuse, misuse, lack of proper servicing, etc. Thus, I have to repeat this advice: You need to be aware of what you need to do to ensure a claim by you will be honored. Leave nothing to chance.

I heard that the CIA forced Porsche to produce a certain amount of cars (@10%) to have a CEF on or before 39,000 miles. Interesting reading about the proof was posted elsewhere.

Dammit, OP, you made KK say "CEF."

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All Porsche Flat Six engines from 1963 - 2008 had an Intermediate Shaft. The M86-96 and some M87-97 had an underperforming ball bearing on one end. The others had pressure lubricated shell bearings.

I still cant believe this but I was able to find what the OP was looking for. The responsible worker that actually assembled the known defective IMSB's out there has been identified. He goes by "Bob" but his real German name is "Hrodebert". We have proof, really!

Is there a problem with IMS bearings?

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New here, ain't cha?

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Kidding! Had two ims bearings replaced in my Cars...lol. Just tired of the threads as well. But i am sure i probably started one once!

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It is always something. A month or two ago was looking into a new Dodge Challenger RT. Visited a couple of forums and started reading threads about problems. Found out there's an issue with believe it or not the timing chain of the 5.7L V8 engines. My God, the chain's about a short as it can be and that area of USA big block engines has been the least amount of trouble of relatively trouble free USA big block engines since Noah was a boy.

...

its obamas fault

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Are you the one that always comments on CNN articles?

My thanks to all who actually replied to the questions posted...even if reluctantly. When I searched other threads on the subject I felt I was reading the last chapter of a book over and over. Maybe I was just late to the party. I will reread my warranty just to be 100% sure of its coverage. And maybe I'll be one of the lucky 92%. Sadly my car may qualify as a garage queen since in eleven years its previous owner only drove it 39000 miles, or just under 4000 a year. Maybe with a little luck my using the car as my daily driver will breath some life back into the seal.

FWIW, some people still think that a used car with fewer miles is BETTER than a used car with a sh*t-ton of miles. Enjoy racking up the miles!

Don't feel bad. My 04 had 21,000 miles on it. I just bought it a month ago...but did have the bearing done.

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I mostly disagree with the thought that it is better to buy a higher mileage 996 than a lower mileage one. A used car with fewer miles IS better than a used car with higher miles. True for 996s too. Spend $2,000 or less replacing the IMSB instead of spending two or three times that amount on other worn out components caused by higher miles. You'll end up with a tighter, fresher and more valuable car.

For me, if a low milage car has been atleast driven regularly, it has a better chance than a car that sits for weeks and then goes for a long long drive and then sits for a couple of months, etc. On behalf of higher milage cars, back in the early ninties I bough a 12 year old 308 gtsi with 88k on it. Most Ferrari owners have heart attacks at the thought of those miles. I bought the car from the original owner, after sitting and reading every service receipt going back to the dealer's pre-delivery inspection. The car was solid...a daily driver...and that is how I used it for the next two and half years. I sold it for two thousand less than I paid for it, with now 124k on the clock. Only had one break down, on a Friday afternoon the clutch cable snapped. I was back on the road by noon the next day. Sadly the car was heavy and slow but I had a great time with it anyway...until the afternoon that a C2 blew by me on Mulholland Dr. Within 3 weeks the Ferrari was gone and I was driving an RS America.

Gonzo, Holy $#%^! That was funny, clever, and accurate! and, ,,,, John, with the poll failure rate now well over 10%, you would be crazy not replace the IMSB on your low mileage 996.

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nope. but you are the one that removes his sparkplugs and squirts oil in his cylinders if the car sits for more than 2 weeks !

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Damn right. And it's "Marvel Mystery Oil" to you pal.

LOL. I love MMO. I have used it in all my diesels as an occasional fuel additive. I just bought some the other day and dumped it in my current diesel's fuel tank. Great stuff (for diesels)!

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KK, I hope you don't actually believe me because apparently some people do...

Has Jake ever commented on this video from Pedro? Anyone else seen this? You Tube

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I'd be glad to Please post address

If it's an IMSB thread, I want in. . Here's my contribution. .

A warranty is not the answer , a good one will Cost you half of what a good IMS fix costs. I chose the DOF by TunersRS Many have done Rabys fix. You car has some years on it and there are Issues with parts that (Age Out). Pull your engine and change the IMS , AOS, all rubber hoses Water pump, belt and coils. Don't forget the plugs which have probably Not been done.

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It raises 2 questions in my mind: 1. Wouldn't "centrifugal force" also immediately eject any oil directed at it from a feed before it even had a chance to circulate within it? 2. If splash lubrication alone is inferior to the grease-sealed bearing as he states, why are the open LN bearings not failing left and right?

i see two problems with this example 1 oil is flying around not from hitting the smooth bearing seal but from hitting the actual bearings, so there is contact 2 the real bearing is not rotating in a open 1 foot square cube, its in a sealed tube so any splashing oil would splash back into it

Pedro may be correct that the bearing will live longer if it's lubricated, but the science fair demos have got to go. That was even more rinkydink than the techno intake video. Pedro, if you shoot a video with the bearing mounted in a tube the same diameter as the IMS shaft, rotating at some speed that might be representative of the speed at which the IMS turns, with the same volume as an IMS shaft, and the same volume of available lubricant, post it up. I'm a long time fan of Pedro's garage, but the baking-soda-and-vinegar volcanoes are ridiculous.

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I read the book, plot was a bit thin, but didn't go see this movie yet.

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If the oil was directed at the open bearing with sufficient force some (enough) oil would get into the bearing. At higher rotational speeds though less oil would make it into the bearing, but this may not be as bad as it initially reads. A roller bearing doesn't have a big oil budget -- unlike a plain bearing -- and at higher speeds really works best with an oil mist. I dare say pressurized oil would have sufficient force to make it to the bearing. (Pressurized oil manages to reach all the way form an oil jet located down at the main bearing region all the way up to the underside of the piston.) The behavior of the oil in the engine's sump and in the crankcase is quite different than what the video portrays. For one thing as soon as the engine is started the oil level drops. Under normal operating conditions the level probably drops at least a quart and quite a bit more when the engine is being used hard. Some of these oil becomes suspended in the various regions of the crankcase, under the camshaft covers, in the areas where the cam chain and sprockets reside. Thus the bearing is not even touching the oil in the sump as the oil level is way down. But the amount of oil suspended in the crankcase is quite high and there is a rather dense cloud of oil vapor (mist) in the engine. This along with any splashing/sloshing of oil from g-forces is apparently sufficient to keep a seal-less bearing adequately lubricated.

In the video the bearing is being spun by the center with the caged ***** & outer race also spinning at approximately the same RPM. In the car the center is stationary and the outer race is spinning around it, with the caged bearings spinning at some intermediate speed in between the two. Two very different scenarios.

I have a theory: Sometimes, **** happens. Sometimes, it doesn't.

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That was my thought...you don't hear of many LN failures...and that entire bearing is spinning. Whereas in a motor it would not spin like that (meaning the entire bearing)

I would also think...in stop and go traffic, that the oil would - when stopped- return to enough volume to submerse the bearing.

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Is that right? hows it drive the oil pump?

I think he meant no IMS B , at least not the ball bearing type that's used in the M96 engines.

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FTFY

IMS issue? What... its a myth! Typically, M96 (non turbo) 996 owners favor hobbies like Russian roulette, penny stocks, and skydiving -- forget the backup parachute, that's for 993, Turbo and GT3 owners! If these things don't appeal to you, more than likely you bought the wrong car!

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That is what I meant, and I stand corrected. Wouldn't want to get Quad upset.

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If that's true then there should be an IMS Benghazi thread.

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Let's not forget that the turbo engine is an M96 engine!

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That's not a theory; that's life.

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Clarification has been made. thanks!

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Depending upon the source the Turbo engine (M96/70/70E) has an intermediate shaft, though some sources refer to it as a lay shaft. It is not a full length of the engine shaft like the IMS in the M96 engines though. But it does serve the same function. It is driven by the crankshaft via a gear and runs in plain (hydrodynamic) bearings. It has sprockets which drive the chains used to spin the exhaust cam in each of the heads and just like the 996/986 engines the exhaust cam then drives the intake cam. The oil pump is driven by this shaft by IIRC an external spline that engages an internal spline in the end of a gear pump shaft.

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I wouldn't think that. An idling engine is going require around a quart of oil that is going to be somewhere inside the engine just not in the sump. (Dual overhead cam (DOHC) engines have big oil budgets compared to over head valve (OHV) engines. While even a 6.0l OHV valve engine (like the one in my GTO) can get along with just 5 to 6 quart oil capacity even a lowly 2.7l Boxster DOHC engine requires something over 9 quarts of oil capacity. It has that extra oil to ensure sufficient oil available at all times.) How much this (est.) loss of a quart of oil drops the level in the sump depends upon the area of the sump but I would have to estimate (via eyeball) it would cause the level to drop enough that no part of the IMSB would be submerged in oil. Thus the bearing would have to rely upon splash if there was no direct oil feed. I have to admit the oil sump of a running engine is quite a dynamic region and the oil in this sump is also quite dynamic. There is a large chain sprocket which has a large chain around it spinning just inward of the bearing. What this sprocket/chain does to the oil if the oil level is high enough the sprocket/chain contacts the oil is anyone's guess. It might act to lower the level in the sump at least in its vicinity but it may also help in some way splash the bearing with oil. It would be interesting to have a view port into this region and make a movie of the oil under varying RPMs.

If immersion and splash lubrication were insufficient, all open bearings (LN, others, and the '06-'08 that people have removed the seal from) would all fail in short order. But they don't. In fact the original factory-fit bearings that last into triple-digit mileage are the ones whose seals deteriorated enough early-on to allow splash/immersion lubrication.

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There is some truth to what you say. OTOH, there are not a significant number of engines equipped with naked/exposed bearings in service. Furthermore, a number of these are probably used in such a way the bearing is not highly stressed/loaded and mediocre splash lubrication (if it is mediocre) is sufficient. IOWs, the kind of usage that helped bring about premature IMSB trouble is the just the kind of usage that is tolerant of splash lubrication. Maybe. Or maybe I'm all wrong in my assumptions and the splash lubrication is quite adequate. No one can say for certain. I will just continue to follow as best I can as to how various solutions to this IMSB issue pan out over time.

Well from what I've managed to learn, regarding the OEM bearing the more the seals have given way, the longer the probability of survival. That seems to support that splash/immersion is more sufficient than an almost-sealed bearing where dirty, contaminated grease mixed with oil is allowed to wear away the innards. And I was re watching the video on the direct oil feed showing how centrifugal force ejects the oil, and I was thinking, squirting oil at a spinning ball bearing would have a similar result as peeing into a running fan would it not

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Depends on how much air is being blown.

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Lol when it comes to the IMSB issue there's quite a lot of it, mostly hot

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Lubrication is over rated. Its like adding ketchup to a perfectly condimented steak. Don't get me started.