Can someone please tell me about the IMS bearing, and how this plays a part in the distinguishing between the 997.1 and 997.2?
Thanks for any help.

 

Search is your friend, there's tons of info on this.

997.1 has an IMS, 997.2 doesn't have it at all.

IMS is a part that is known to fail. It's not likely to fail, but when it does it can be catastrophic and take a lot of the engine with it. LN Engineering sells a kit to replace the IMS with a beefier one, but I believe it can't be installed on all 997.1 engines (some have different designs than others). The part isn't expensive, but the labor is. If you're getting a clutch done at the same time you'll save a bunch.

Others please feel free to correct if I got something wrong.

 

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I actually find the lack of responses to this thread somewhat refreshing. I personally believe the 997.1 IMS "issue" has been completely overblown, so the fact that few people have chosen to comment tells me they are tired of talking about it and have moved on. I hope this is the case (not sure), but if it is, it's good for our community. As owners we can't let happen to the 997.1 what happened to the 996. There's a reason why the 996 perception (and prices) are in the gutter, and the owners of those cars need to accept some of the blame.

Sean

 

+911

please use search OP. or google, you will have 30 pages of responses.

 

In a nutshell the 997 IMS bearing problem was predominantly an issue for early 2005 MY M96 and M97 motors, which had the small single row IMS. This can be relatively easily replaced as a preventative measure, and if done while replacing the clutch saves money on labor.

Late model 2005 and 2006-2008 MY vehicles have a larger single row bearing that fails only very rarely, but you do have to completely tear the motor down to replace it. As it fails so rarely, it really is not worth doing this.

The 9A1 motor in the 997.2 does not have an IMS.

According to the Eisen IMS Class Action Lawsuit the small single row bearings have a 8% failure rate, and I believe LN have calculated a 10% failure rate. So while it is a relatively low risk, 1 in 10 997s with the small bearing are likely to experience IMS bearing failure.

Bear in mind there are also other issues with the IMS, like drive gear slippage. The bearing is just the main problem for the IMS.

 

In the same vein the current Excellence tech notes recommends NOT mindlessly swapping out your waterpump at XXX miles. Who might be benefitting from all this "the sky is falling" preventative maintenance advise? How often is the post "Changed bearing or pump" followed with the observation "It was fine"? The tech author recommends using all senses "except taste" to monitor the condition of your motor. Makes sense to me