The most discussed
bearing in motoring.

The intermediate shaft bearing applies to the M96 and M97 engines — broadly the water-cooled Boxster, Cayman and 911 from the late 1990s through the 2000s. Porsche moved to a direct-injection engine at the end of that period which does not use the same arrangement, so later cars are not part of this conversation at all. Establishing exactly which engine is in the car in front of us is the first step, because the bearing design itself changed during the production run.

Most of these engines never suffer an IMS failure. A minority do, and when it happens the bearing releases debris into the engine and the outcome is frequently a rebuild or a replacement. That combination — low probability, severe consequence — is exactly the kind of risk that gets discussed disproportionately on the internet. It deserves attention and it does not deserve panic.

The rear main seal weeps oil at the joint between engine and transmission, and it is common on these cars. It is a seal, not a catastrophe. Because it leaks in roughly the same area, it is regularly confused with the IMS in online descriptions and occasionally in shops. They are separate components with very different implications, and telling them apart is a diagnostic question with a definite answer.

We cut and examine the oil filter media for ferrous and bearing material, which is the most direct evidence available short of disassembly. We check for play and for the characteristic movement that indicates a bearing that has begun to fail. Where there is a leak we clean the area, dye it and re-check to establish whether it is the rear main seal, the IMS flange, or another source entirely rather than guessing from the location. Full fault memory and a road test alongside. That is a Level 1 Testing session at $285 flat.

Reaching the IMS bearing and the rear main seal requires the transmission to come out. So does replacing the clutch. If your clutch is anywhere near the end of its life, doing the bearing and the seal at the same time costs a fraction of what doing them separately would, because the expensive part of the job is already being done. This is the single most useful piece of advice we can give an owner of one of these cars: plan the work around the clutch rather than around anxiety.

Several approaches to this bearing exist, and they differ in design and in what they ask of the engine. Rather than make that decision for you on a web page, we will look at your specific car — engine variant, bearing type, mileage, condition and how you use it — and talk it through with you before anything is ordered. What we will not do is quote a bearing without first establishing which one your engine actually has. Every repair we complete carries a 3-year/36,000-mile warranty.