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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
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YOUR RESEARCHAnother IMS Data Point
Reported or suspected cause
almost unheard of
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
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Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
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Reported cause
I hear of lots and lots of these getting replaced on the internet, but when I talk with Porsche techs and parts people in the real world (friends of mine that don't troll the net looking for issues) the problem is almost unheard of.
Leading evidence: 'almost unheard of' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'almost unheard of' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Inspect ***** & races' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause · Original poster
Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
While they were in there, they installed the new IMS and a new clutch for only the cost of the parts and 4 additional hours of labor.
Replace before, even though i didn't have records of it
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed
I replaced my IMS bearing with the LN upgrade two weeks ago myself on my '03 C4S (83K miles).
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Suggestion
I highly recommend doing it, I ended up replacing that along with the clutch and rear main seal, everything only took about 10 hours to complete, and was well worth it, the IMS bearing wouldn't have lasted another week had I not replaced it.
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Suggestion
So, the original poster uses non-recommended oil, spends thousands on a warranty and parts; there's no evidence that the oil leak had anything to do with an IMS failure.
Replace before, even though i didn't have records of it
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
almost unheard of
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
I hear of lots and lots of these getting replaced on the internet, but when I talk with Porsche techs and parts people in the real world (friends of mine that don't troll the net looking for issues) the problem is almost unheard of.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause · Original poster
Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
33 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T075545Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Background:
I purchased my '99 996 two years ago with 53,000 miles. One owner and immaculate with a great service history. Having read about IMS failures, I elected to purchase a 2 year/24,000 mile warranty, the first time I've ever got an extended warranty on a car since I do 99% of my own work. My plan was to install the LN Engineering IMS bearing as a preventative measure as many here have done once the warranty expired. The car is my daily driver and sees about 1,000 miles a month. Since the first oil change, I've been running Schaeffer 9000 5W-40 due to its high shear strength number and changing the oil at 7500 mile intervals. Fast forward to two weeks ago when I noticed an oil spot on the garage floor that was coming from the RMS/IMS area. With about 2,000 miles left on the warranty, this looked like a good opportunity to get the IMS bearing done by a pro and only have to pay part of the labor.
The bearing:
Dropped the car off at Steiner Racing Sports in Houston for the repair. Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner. So they installed the new RMS and IMS upgraded bearing, as well as the clutch disk, which had about 35% of its life left.
I brought the bearing home with me to disect it and see what I could learn. The bearing felt almost, but not quite, as smooth as new bearings (wheel, transmission, etc, never handled a new IMS bearing). Oil would seep out of the seal when layed on edge. Popping the inner seal revealed that it was full of what looked to me to be motor oil, not grease. After pulling the outer seal & both bearing cages, the ***** showed no pitting or wear, nor did the inner or outer race. Also, there was no sign of any flaking or other wear.
It is worth noting that the outer bearing surface did show a fair bit of residue from the block. I can post pictures of the bearing later today if anyone wants to see them.
+1 for NO GREASE... never seen one yet with grease in it.. they seem to all be using oil as lubricant....old stinky oil at that...IMO it stems from the shaft itself being sealed (thermal expansion of the air inside)
anyhow, you're good to go now!
I'd love to see what you found.
I'd also love to see any other bearings that have been removed that are in various stages of impending failure, discolored, brinelled, pitted, etc. I hear of lots and lots of these getting replaced on the internet, but when I talk with Porsche techs and parts people in the real world (friends of mine that don't troll the net looking for issues) the problem is almost unheard of. I spoke with an employee of one of the largest P dealers on the West coast that ownes a 996 C4S. He spent over a dozen years as a service writer and moved into sales a couple of years ago. He seemed very familiar with all of the potential 996 ills, and when specifically asked about the IMS, he stated he saw a couple of broken shafts on the earliest 996s and the shaft/ bearing was updated early on.
I can't help to think if the IMS bearing failure is immenent, there would be tons of dead '97, '98, '99 '00 and later Boxsters for sale for scrap prices. Maybe there are? Just my opinions form being heavily into P cars for decades, and real heavy since '97. I'm not denying that there is no intermediate shaft bearing related issue. Just not 100% convinced that there is. Sure lots get replaced, and if it concerns you and helps you sleep better at night, I guess it's worth it. Peace of mind is a great thing, insurance have made billions off of it, lol. Honestly not trying to be cynical.
Well, I dont think the bearing fails slowly, So I dont think you would really find pitting unless you were really close to losing that bearing.
Its my Opinion
the bearing fails due to the seal failing and letting engine oil in to the bearing and not letting it back out.. This also allows oil to build up oil in the IMS tube. It's
MY OPINION
again... that the oil in the IMS tube breaks down and burns black. This oil in turn then seeps into the bearing as the bearing is left sit at rest while the car is parked.. So this bad, burnt oil is in the bearing all the time.. This causing it to wear from lack of a good lube source. Im not willing to bet my engine on it.. But I feel if you would pull the outter seal off the stock bearing.. It woudlnt fail.
also keep in mind as Kyle states this "bad oil" is contaminated with hydrocarbons and unburned and burned fuel...it therefore is corrosive and etches the *****/races if left too long (which is why running the motor is betyter than letting it sit for long periods
and as Kyle stated - this is my opinion.....
So drill a series of holes in the Intermediate to allow oil exchange and have fresh oil on both sides of the bearing?? No etch no itch everyone is happy and comfy
yes, but you should remove the shaft to drill it out...= tear motor apart while doing so I would advise pinning the gear on the end too - why... because they can turn causing the timing on one bank to shift
yup
wait, this is still my opinion
OK, here are a few pictures. It is interesting to note that the seals looked ok, but the oil that came out looked just like the oil you would expect to find in the crankcase. Same color, smell, & feel. The oil on the blue paper towel is some of what came out of the bearing. One could theorize that this is a good reason to do frequent oil changes & use really good oil.
Steiner had a dead 3.6 on an engine stand that the IMS bearing had taken out. The bearing felt a bit rough when you turned it, but not that bad.
This is sure to start a flame fest but this constant chatter about sealed bearings is killing me.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
I recently took my 996 in for oil service at a porsche specialty shop thats been in business for about 25 years. They race, etc, busy place. I asked the service manager what he thought about the IMS failures.
He said they have recently been inundated with questions about IMS due to the internet chatter. He also said they had never seen one, or knows anyone that has ever had an IMS failure.
But he did have a customer requested preventative IMS replacement scheduled for the following week..
Before we perfected the IMS Retrofit procedure the only thing that could be done was seal removal.. Now that the retrofit procedure is so perfected its not really more expense to just replace the bearing while the flange is removed. The labor difference is less than two hours at that point.
I have never seen an issue where a splash lubricated roller bearing could be "over-lubricated".
Hey I just replaced the IMS bearing in my 996, because of all of the talk about it. And, good thing I did because it was absolutely shot. It was a 6spd 80K miles well taken care of, but by no means was babied.
I highly recommend doing it, I ended up replacing that along with the clutch and rear main seal, everything only took about 10 hours to complete, and was well worth it, the IMS bearing wouldn't have lasted another week had I not replaced it.
Here are some pics of my ims bearing. When I got to the bearing it was slightly leaking, when I got it out their was no burnt oil and almost no oil in the tube.
After reading the stories about it, and then when I was at IPB autosport an 01 came in with the bearing failure making me decide to do it, I got all the parts and went ahead and did it. I have my own hobby shop that I put a lift in that me and my son (when he is home from college) play on our cars. So it made the job a lot easier, did the whole job in ten hours. The car just turned 80K was well taken care of, driven like it supposed to be driven, and it was a manual.
DUDE!!!
that is the second worse bearing I have seen! I hope you think you "did the right thing" because I doubt it would have been long before that one gave out!!!!!
WOW!
edit - I see your earlier post.... no sh@t it would not have lasted long....no noise, no "signs of failure"??? but holy crap it was on the ragged edge!
That bearing was on the way out.. The reason why their was no oil in the tube is because BOTh the inner and outer seals had been compromised allowing the oil to drain back out of the tube. This is what generally creates the "IMS OIL LEAK" but not in all cases.
You dodged a bullet on this one by doing the procedure electively. Good for you.
Jake, how many have you seen that bad that still run? - saw (1) came in for clutch and "happened" to get caught at the dealer, then towed over to the shop - it was saved but man, close!
Maybe five total. Generally when they look like that its already gotten bad enough for valve/piston interference and the collateral damage takes the engine out before the bearing completely grenades.
I replaced my IMS bearing with the LN upgrade two weeks ago myself on my '03 C4S (83K miles). I never disassembled the bearing. Instead I sent it back to LN Engineering for them to have for research. Now I'm curious as to how my original bearing looked. From the outside, the bearing looked fine. But you can't judge a book by its cover. I'm just happy to have peace of mind now after the replacing the IMS, especially after seeing this thread.
even though I'm out of the game, I'm curious if Porsche has ever recommended changing the IMS bearing as part of normal maintenance? Or would that be admitting there was an inherent problem?
So, the original poster uses non-recommended oil, spends thousands on a warranty and parts; there's no evidence that the oil leak had anything to do with an IMS failure. I'm going to consider this 996 IMS Myth Busted #4.
What exactly is your point? Yes, I use an oil from a small company who has not gone through the trouble of getting it certified by Porsche. I learned about this oil from LN Engineering, and based on its numbers, is as good as anything out there. I paid two grand for a bumper to bumper warranty when I bought the car. The warranty paid for a rear main seal at 22 months. While they were in there, they installed the new IMS and a new clutch for only the cost of the parts and 4 additional hours of labor. The bearing appeared to be in great shape and very well might have lasted for ever. Who knows? The thing is, now I have piece of mind, which is worth more than the $1000 it cost me to install the bearing.
You might want to look at that Schaeffer 9000 5w-40 oil again...
I did via the material safety data sheet at Schaeffer's web site.
Here's the link:
http://www.schaefferoil.com/cmss_fil.../MSDS/9001.pdf
First off I note it is a diesel engine oil. What possesses owners of Porsches to run diesel engine oil in their gasoline engines is beyond me.
Besides being a diesel engine oil (which is not even approved for use in Porsche's diesel engine Cayennes), you know why Schaeffer probably didn't bother to submit this oil to Porsche for approval? Because Schaeffer knew the oil would not be accepted. Based on the list of ingredients the oil contains among other things mineral oil.
Use google to search on those CAS #'s and find out what's really in the oil.
I did and besides mineral oil, I found POA (which is good btw) but two of the other 4 ingredients are paraffinic oils.
Based on the search hits, one's primarily used for vacuum pumps. The other is used in pesticides. But this oil is bee friendly.
This oil may be a good oil for diesel engines but save for its a 5W-40 characteristic this oil has no other qualifications for being in a Porsche gasoline engine.
Sincerely,
Macster.
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