Second link has an interesting advice -
'Use a higher viscosity motor oil. There are several Porsche approved oils that are 5w40, rather than Mobil 1 0w40. Use of an oil with more Zn and P or moly extreme pressure anti-wear additives may improve engine life. Timken Falex bearing tests tend to indicate increased load capacity and less wear scarring with oils with high levels of moly as documented here and may prolong the IMS bearing life. To learn more about motor oils and which ones might be better for your Boxster, Cayman, or 911 model, click here.'

It is a first time I see well argumented advice why one should use higher viscosity oil. Quite interesting.

I am a bit nervous though to put anything else than officially recommended mobil 0w40 into my car... Can anybody comment on this?

 

I suspect that if the rate of IMS failures was even 1%, it would still be too high of an exaggeration.

 

Gents,

could somebody intelligently translate exact meaning of this below:

"According to PET, here are the engine numbers for single or double row bearings* up until late 2005 then 2006 and later engines which received a larger, more durable single row bearing. *Courtesy of Scott Slauson http://www.softronic.us Thank you Scott!

Boxster: Double Row: up to 651 12851 (M96.22) up to 671 11237 (M96.21)
Single Row: from 651 12852 (M96.22) from 671 11238 (M96.21)
996: Double Row: up to 661 14164
Single Row: from 661 14165"

So, is IMS failure considered to be fixed on single row bearings? I see my 3.6L engine is M96.05 type and its number is 69611xxx - so is it a single row bearing type or double row? I am confused a bit.

 

Thanks for posting this info for everyone. I also did extensive research on the web, forums and local Porsche dealers/independent in the San Francisco Bay Area on the IMS issue before buying a 997. Also had read the article in the link as well. Ultimately I decided to pass on an '05 C2S launch edition and ended up getting an '06 C4S due to my concern about the dual row IMS design on the M96 and '05 997 models.

I could not find any posts or articles about an IMS failure on '06-'08 997 models, but I found posts of M96 failures and '05 997s, including some C2s launch editions. The service managers at the 3 Porsche dealerships in my area that I spoke to could not recall seeing any IMS failures for '06 or later 997s (also the same answer when I contacted some indy shops in my area, although they would be unlikely to see this since repairs would be done under warranty at the dealer). Stevens Creek Porsche in San Jose told me that IMS failures will usually occur within the first 30K miles and have mostly been on Boxsters and 996s.

This obviously no guarantee that the IMS shaft on my C4S won't break, but I sleep a little better at night knowing I have likely lower odds of an IMS failure with my C4S than than the '05 launch edition I had almost bought. And yes, I drive the car "like I stole" every chance I get!

I'd be curious to here if anyone on this forum with an '06 or later 997 has had an IMS failure.

 

My 05 997 had 36700 miles when the went. It is certainly less common in later year 05 and up models. But it does happen.

 

I agree with what has been said before. I also did a lot of research on this subject since I had the IMS failure in an S Boxster 01. One thing I would like to add is that in May of 2005 Porsche redesigned the block above the IMS to add some strength to it. You can see this from the outside by some horizontal like lines above the shaft. It seems over a period of time the block would change to allow the shaft to move a little causing the leak and thus failure. In my case the carrier bearings for the chain did not at one time get enough oil and when the car was running you could hear a chirp noise about once every 5 seconds.( A TIME BOMB) From my research there hasn't been enough activity on the 06 - 08 to tell if Porsche's fix has worked. Let's hope so.


Blair
06 C4S Artic Siver with Tan Interior

 

I am getting the impression that the design change to the IMS happened during the middle of MY 05? If that's the case, how can one tell if a certain car is built before or after that date? Is it safer to just stick with the '06 then?

Thanks.

 

Like the linked article said, the only way to be sure you have the upgraded IMS bearing is to actually look at the bearing. A indy shop or your dealer should be able to check this for you but it will cost you!

Apparently the IMS bearing was beefed up during the MY05 model year and saw a full transition from the start of MY06. So, there should be 05 997's that came with the upgraded IMS bearing. Again, there is only one way to know for sure.



Jason

 

Thanks everyone for this valuable thread on IMS failures. I've got an '05 C2S built in late '04. I bought it "pre owned" from the USA and had it serviced at our local Porsche dealer. At the first visit the chief mechanic said he believed that I had a replacement engine. He based this on no Cosmoline on the engine. I wasn't worried about this as I know they were replaced for a variety of reasons on the early build cars. Since the IMS issue came up I've been trying to find out by serial number if indeed I have a replacement engine and if so where does it fit into the whole scheme here. Neither the current dealer or the original selling dealer had, or would give me that information! Although I've had absolutely no issues with the car, inspite of several track days each year, I to am worried about the long term durability. I saw the article in Excellence and wondered if you can actually see the different case design with the engine in place or does it have to be removed? Thanks again for the info.

 

Just read the articles (lazy boy) Transaxle has to be removed to see the IMS reataining collar.

 

If I am reading the information properly it appears that all 997's with VIN #'s from 661 14165 and higher have the redesigned single row bearing IMS.

Would this be correct?

 

Just purchased an 05 997S which had the engine replaced by Porsche 3 months out of warranty. Not only did Porsche install an updated engine with the 12mm IMS completely free, but they also placed an additional 2 years warranty on the new engine. Personally, that was the main reason I purchased the car....I too was a little concerned after reading on the engine failures....especially when the repair bill comes in at around $18K

 

I guess that's me . My 02 996 had multiple problems at the same time and 8 years later I lumped it all together .

 

Yeah we have been thru this before so I ask you this. What is your speculation? My problem with amplification of this issue is that newbies doing random searches on the internet might get the impression that 50% of M96 engines suffer from IMS failures and thus total engine failure. When in reality the % is much much lower. Sure, no one can say without speculating that its 5%. But even 5% is pretty bad if you think about it. 1999 with all his knowledge stated that even 1% would be pretty bad on a production car, and I can see his point.

We talk like this is a huge issue... an elephant in the room (or forum)... a black cloud over our otherwise perfect day...you get my point. But in reality the IMS failure issue really hits a very small portion of cars. And, LN Engineering has done a lot of research into why. Why do they fail in some cars and not others? There is no doubt the IMS and associated bearing are a weak point the M96 but are they so weak that all fail or even half of them? No, of course not, outlined in the article are specific reasons that, through research, explain some of the failures. Long intervals between oil changes which can allow impurities to degrade the ability of the IMS bearing to do its job is probably one of the biggest.

It would be fun to do a Poll. Lets find out how many 2005 C2 owners are on the board and then how many have had IMS failures. It would be a small sampling but it would be interesting to see the results.

But my overall point is try to and quiet the "sky is falling" attitude that surrounds an issue that has now been researched, has preventative measures, and even fixes.

Jason

 

Sorry to be extra dense here, but I'm trying to decode this VIN thing. What is the '661' (my VIN doesn't have that designation). And is the 14165 the last 5 VIN digits? I forgot my decoder ring...