Intermediate Shaft Bearing

Ooops, I said it, the dreaded IMS issue of the boxsters and 996’s.  This weekend we tackled upgrading the IMS bearing in a buddy’s 1999 996 C2.  The IMS issue is the main cause of failures on the engines found in the early boxsters and 996’s.  The early design was a dual row ball bearing, followed by the later design of a single row bearing.  Typically failures are seen on lower mileage cars that are driven sporadically.  The theory for this is that the oil is changed less often, acids and water builds up in the oil, which seeps into the bearing (washing away the internal grease, and causes pitting of the balls and roller surface…oil gets in and probably doesn’t get out like it should since the seal keeps the oil from flowing at a good rate through the bearing).  Higher mileage cars don’t seem to be affected by the problem much at all.  In fact, when we pulled the bearing out of this almost 100k mile car, it was near perfect.  Nice and tight with no play at all.

The old repair when the IMS failed or started to make noise, was a new motor to the tune of $15-20k.  Fortunately, there is now a R&R procedure and an upgrade to this issue from LN Engineering.  A little bit of preventative maintenance should solve this problem from ever happening to your engine again.

Because Jim had a lot of other maintenance he wanted to do to the engine, we decided to drop it out of the car and work on it in a more accessible position.  Normally, you can just remove the transmission and clutch assembly, and perform the upgrade like that.

Motor on the ground, time to tackle the IMS bearing.

Cover removed, bearing exposed.  After some prep work we pulled the bearing assembly out.

Old bearing.  Again, it was nice and tight, probably would have gone another 100k miles….but you just never know until you go in there and check/replace it.

This is the new LN ceramic bearing assembly installed.  Note you can see the balls in the bearing, this is to allow engine oil lubrication in and out of the bearing without any interference from a closed seal.

Custom LN billet IMS housing going into place.

With that, this car should be bullet proof for as long as the rest of the motor lasts.  Also on the list was oil cooler seals, new OAS, chain tensioner pads and chains, coolant tank, spark plugs and seals/tubes, then the motor will head back into the car.

996BoxsterIMSIntermediate shaft bearingIntermediate shaft failureM96Porsche

More from the Blog

Leave a Reply