2005 997S large IMS bearing question

Hi All, I have a 997S that was built in June or July of 2005. About 40K miles on the car at this point. I'm not absolutely sure which IMS is in the car although I believe 2005 was a transition year for it and that probably it has the larger non-removable bearing as it was built almost at the end of the production year. I asked the head tech at a large Porsche dealer whether he had ever seen a car with the larger IMS fail and he said he had not. I would appreciate the collective experience of the group with this question also - and also if failures of the larger bearing are indeed that rare, whether I should just have the Direct Oil Feed (from Pedro's Garage) installed without a new bearing as a preventive measure. Or just have the seal removed. Thanks in advance for any opinions or experience with this issue.

The only way to know for sure which bearing you have is to open the hatch and inspect it. What you do from there if it is the larger bearing is up to you. There are pros and cons for each. The failure rate is quite low but they do fail occasionally. One solution is to just drive the car, get the revs above 3K when driving and change the oil frequently. That means at least once a year (or every 2500-3000) for a car driven occasionally. If you plan to track the car, you should change the oil a bit more frequently. Also put in the X51 oil baffle (or the one from EBS racing) to prevent oil starvation while tracking the car. Use good oil. Don't store the car with dirty oil, put it away with fresh. My '06 Cayman has the large bearing with the seal on and 95K on the odo. Oil analysis shows normal ranges of all items checked.

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If you find the 22MM center bolt when you take the car apart, you have the non serviceable IMS. If that is the case, you best bet is to remove the rear seal from the bearing and put the car back together. Adding a pressurized oil feed does nothing but add expense and potential issues down the road.

Thanks Tony and JFP, much appreciated for your input. I have seen one service provider on the net that claims its possible to determine which IMS is in any specific car within 15 minutes of labor cost. But they also don't describe how they do it, claiming it is proprietary information. Sounds like a scam to me?

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Run away, quickly.................

change the oil frequently. When you're ready for a clutch, you'll be in there and have a look at that time. I think pulling the seal is a good idea if you're in there and you find it is the larger type.

I have a big nut motor in my 2002 996, replaced under warranty at 40k miles by the original owner. I verified this when I changed the clutch a year or two ago. I posted on rennlist a while back asking for someone - anyone - to provide an example of a big bearing failure, and heard nothing (except bullsh|t of course). As far as I'm concerned, the big bearings don't fail - and once again I would just *love* it if someone could post evidence that they do. I'm not talking about stories, I'm talking a photograph of a failed big bearing. Change the oil and revv the hell out of it. My car has 140k miles on it now and it runs as strong as ever. No funny noises, no drips or oozing. The car has been a treat to own and drive.

I would also like to hear more about this issue as my car is a September 05 Carrera S with only 27k miles on it ,,oil changes every 3000 miles or twelve months witch ever comes first ,,,no issues yet but always a thought in the back of my mind ..........??

Is there a way to use a boroscope or some such gadget, through an existing or newly made benign hole (we'll talk about possible location next...), to see the 22 mm center bolt that's referenced above? I have a slightly older 2005 C2S and the clutch is fine so an engine drop is not in the near future. I will follow the increased oil and filter change frequency and use DT40. I dissected the last filter and saw some pretty tiny metallic flecks (but no where near the horror pictures of some filters that had already experienced a failure or indicative of impending failure). My indy mechanic said "not to worry" after looking at the filter and listening to the warmed up engine. I've read that the M96/M97 "sheds" some metal - but of course, it's all in the details (about what quantity is too much). BTW, with the DT40, I swear there is much less engine clatter when cold and a little less when warm. I also use the LNE spin-on adapter, FilterMag, and mag drain plug.

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No..............

Yeah....its not possible to see what you've got without pulling the gearbox. Good news though is that the clutch can fail without warning. Common failure mode is a collapsed spring plate, that's what happened to me. This happened without a hint of slipping, although pedal effort had increased. If you're lucky the clutch will fail soon and all will be revealed. You'll either replace the bearing, or sleep peacefully knowing your big nut bearing isn't likely to fail...plus you'll have a new clutch. Best case scenario really.

Big bearing failure, like stated above, is very very rare. I too would love first hand accounts (documented) to be shared... I am yet to see a 2005 3.8 with a small bearing. They may be out there, but have not seen one yet. Cheers

The link below is a interesting thread that shows the engine build dates most likely to have the small IMS bearing and the period were the larger bearings started to be used ......... '06 S owners - what's your engine number and production date? - Rennlist Discussion Forums

Jeff Alton - do you agree with the seemingly commonly held opinion that the M97 of this vintage lives longer when the revs are kept "high" (or higher when compared to what (general) drivers think of as the norm). Until I read it in some other Porsche forum, I wouldn't have believed it but I saw what seem to be a Porsche recommendation for minimum up-shift RPMs for the different gears. I certainly agree that no engine should be "lugged" but I'm trying to distinguish between that and having the engine live longer because its lifetime engine RPM average is high/higher. (Which on the face of it seems counter intuitive.) I also agree that not "getting crazy" with the engine RPMs is warranted with cold oil.

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Only one problem with this: In 2004, Porsche moved from the PST II to the networked PIWIS system, and stopped printing any service manuals because they were now included in the PIWIS system. Add in the fact that Porsche has never admitted that the IMS bearing could be extracted with the shaft still in the engine, and only sold replacements as a fully assembled shaft, and this becomes even more questionable.

jchapura, Not sure I have an opinion on keep the revs high idea. Agreed a motor should not be lugged, but hard to have empirical data that shows a particular motor was driven with "higher revs" and that it lasted longer....

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Just replaced my IMS bearing today on my 2005 C2S with an M97 3.8 engine. Build date was Oct 2004. The original bearing was in perfect condition after 46k miles, my clutch had died though. Now I'm running with the LN engineering single row pro dual bearing.

Thanks for the post HuntR3. What is your engine code? Did your bearing still have grease in it when extracted? Had you ever seen metal particles trapped in the oil filter medium? Did you generally use Mobil 1? Generally, how long between oil changes?

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Thanks for the data point!

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Jorian's 997 reportedly had its IMS bearing changed prior to his having bought it Jeff. Can't say if it was documented but I think a reputable report. I've heard of a few early 997 3.8 which have had bearings changed, hence were equipped with small bearings. Believe the change happened little bit later in 2005. I was a bit surprised in fact when I found out my 3.6, which was installed in 2005, had the big bearing. I was all geared up to change it out and whoop, there it was.

Actually my build date was Sept 2004 and the sell date was Oct 2004, either way, early 997 build date. Engine code: M9770168502456 I didn't change the bearing myself so I can't comment on whether the grease was packed in but the mechanic said it was in perfect condition and there was no indication of wear on it. That's the original IMSB in the pic I attached above. My engine has had Mobil1 0w-40 for its entire life, changed on average every 1-2 years around 4k-6k miles. I'll be changing it at least every year and have since I bought it and I've cut open the oil filter the past couple of years and found nothing more than a few tiny specs of metal. I'm running with a magnetic drain plug too and I've noticed this engine doesn't really consume any (much) oil over the course of a year. With the last oil change this spring I sent it off to Blackstone Labs for analysis and there were no signs of anything abnormal in the oil except the viscosity of the Mobil1 0w-40 was starting to shear after only 4k miles so I'm going to try running with Motul Xcess 5w-40 now.