Which 996 models affected by IMS failure?

[rjrandalls]

Sorry for the question that's likely been asked here many times. Which specific 996 models are affected by IMS failure? Carrera, 2S, 4S, turbo? All but the turbo?
Also, anybody know whether the IMS retrofit is a permanent one time, or regular replacement thing?
I'm looking at a 2002 74k mi C4S.
Thanks,
RJ

[Elombard]

all Pcars with the M96 motor design have that. All box, cayman 996,997 from 1997-2008. Some have higher failure rates then others. Turbos dont have the M96.

[Duc Hunter]

All 996 normally aspirated cars were, none of the turbos were. That said, as I understand it, they make noise and can be changed long before a catastrophic failure. And replacement now there are many improvements that should prevent it in the future. This makes 996's a steal for the performance you get. The initial IMS bearings were greased and sealed for life. The problem seems to have been that when the cars are only driven a very little bit (like 1000 miles/yr) the grease dries out. Porsche changed the bearing, eliminating the inner seal, so engine oil gets into the bearing lubrucating it. The Indy's in my area have never seen one of those fail.

Edited - I forgot to add that my mechanic, who used to work for Porsche, said that only about 5% of these cars actually had failures. Again the failures are mostly caused by low mileage

A good Indy should be able to tell if the IMS is making noise during a PPI. I would question one who just says "it's a 996, it needs to be changed." We have one of those here in town. Good luck!

[Drisump]

This isn't really the proper forum to pose this question. This forum is specific to pre 89 911's so what will be offered is limited since few of have a 996 or have ever had a 996. That being said, a buddy of mine has a 996 and has researched the issue exhaustively. The issue is a concern on most common 996/ 997 variants including the Boxster. The Turbos and GT cars (2 and 3) have a true Dry sump motor with no IMS....therefore no IMS issue (a Mezger engine). There are certain versions of the IMS bearing that have less problems than others and a wide variety of solutions available, oiled, ceramic to name a couple. 996's certainly give a lot of fun for a modest cost, even the Turbos are not terribly expensive so at 400hp and beyond......wow! Cheers and good luck.

[Elombard]

Over on the 996 forum on Rennlist there is a Poll that is stickied to the top. It documents the failure of users on that forum. Gives you an idea of how common it is. Although I would not take it as the last word its interesting to look at.

[fastfredracing]

Here is mine. The IMS is fine.

[stlrj]

Originally Posted by Drisump

This isn't really the proper forum to pose this question.

It is if contemplating a move up to a 996.

[Drisump]

Does the OP already have a pre 90 911? All I'm saying is that there many participants on this forum that do not know anything about 996's.

[dtw]

Originally Posted by Duc Hunter

All 996 normally aspirated cars were, none of the turbos were. That said, as I understand it, they make noise and can be changed long before a catastrophic failure. And replacement now there are many improvements that should prevent it in the future. This makes 996's a steal for the performance you get. The initial IMS bearings were greased and sealed for life. The problem seems to have been that when the cars are only driven a very little bit (like 1000 miles/yr) the grease dries out. Porsche changed the bearing, eliminating the inner seal, so engine oil gets into the bearing lubrucating it. The Indy's in my area have never seen one of those fail.

A good Indy should be able to tell if the IMS is making noise during a PPI. I would question one who just says "it's a 996, it needs to be changed." We have one of those here in town. Good luck!

1. 996 GT3 - normally aspirated - has the same Mezger-based engine as the 996tt and GT2. As such it does not suffer from the same IMS issues as the M96-based cars.

2. The IMS failure is not necessarily preceded by noise. If the bearing gets noisy, it has usually already spread metal shavings throughout the engine.

3. I'm not even sure where to begin on your claims on the low mileage and dry grease issues.

4. Never heard of the updated factory bearing with the seal on only one side. Got a link to that?

[Cook&Dunning]

Another point worth noting - from 1997 to ~2005 the ims fix is a "relatively" easy thing that can be done with the engine in place - there are several companies that offer this ims fix. Some owners make this a regular maintenance item - say when you first get the car, and then when you change the clutch. From ~2005 - 2008, however, the only way to replace the ims is to drop the engine and split the case.

[walt]

Fast Fred, was that damage to the cylinder wall caused by the water pump impeller failing? What are your plans for it.

[Tippy]

The 996 engine suffered porous blocks, slipping cylinder sleeves, IMS failures, and other things that led to complete engine failure, but that thing makes nasty power once turbocharged.

Just have to roll the dice, but do the Raby IMS bearing changeover for sure and hope for the best.

[wolds]

So I just purchased an 03 C4S from a fellow Pelican member the first of April. The car had 69K on it when I purchased it and now has 70K. As I'm writing this the car is having the LN bearing installed by Kraftwerks here in Ohio. The cars are a good value and the IMS issue needs to be budgeted when purchasing. I love mine and plan on driving the #@+? out of it while it's in my possession. Warren

[KNS]

Originally Posted by Drisump

The Turbos and GT cars (2 and 3) have a true Dry sump motor with no IMS....therefore no IMS issue (a Mezger engine). .

All flat six Mezger engines, air cooled and water cooled, have Intermediate Shafts (IMSs).

[Duc Hunter]

The biggest problem I see with 996's is that the headlights get cracked from the sun, and they're very expensive to replace. Ugh! As far as IMS problems, if you know what you're walking into, and budget changing one as mentioned above, you will pick up a great car for a very inexpensive price.

[Brian 162]

What about cylinder scoring? I know of at least 3 owners of 996's in the last 6 months that have to deal with cylinder scoring.

[Elombard]

I have been reading about the scoring with 997s as well. I think its still pretty rare. the scourge of the enthusiast car - they get picked to death.

[Drisump]

Originally Posted by KNS

All flat six Mezger engines, air cooled and water cooled, have Intermediate Shafts (IMSs).

My mistake, they all had an IMS but the A/C and the GT cars had oil pressure lubed bearings vs the roller bearings in the problematic engines.

[boyt911sc]

Originally Posted by Duc Hunter

The biggest problem I see with 996's is that the headlights get cracked from the sun, and they're very expensive to replace. Ugh! As far as IMS problems, if you know what you're walking into, and budget changing one as mentioned above, you will pick up a great car for a very inexpensive price.

Duc,

What would be a typical budget to fix or repair the IMS in 996 cars? I have rebuilt more than a dozen 911 engines but never been near a 996 engine. Would DIYers be able to perform this repair at home? What special tools are needed? Thanks.

Tony

[Elombard]

^ there is a couple of 996 engine rebuilds done DIY that are pretty well documented over on Rennlist in the 996 forum. Doesn't look too bad but there are some things you would not know to look for unless some one told you and some special tools.