Porsche IMS Bearings

Porsche IMS Bearing Problems, Failure and Repair San Diego

The IMS (Intermediate Shaft) bearing is a critical part of Porsche’s internal structure.  The Intermediate Shaft supports the timing chains, and Engine Oil Pump drive.  Porsche used the Intermediate Shaft in all Boxster engines Model year 97 thru 08 and all 911 Engines model year 99 thru 08.  In 2009 Porsche deleted the Intermediate Shaft altogether.

To perform this auto repair service the IMS bearing the transmission needs to be removed and then a special tool is inserted into the IMS bearing and it pulls it out of the Engine Case.  This is on all models thru 05.  Model year 06 thru 08, the IMS bearing is irreplaceable without taking the entire engine apart.

At Charlie’s Foreign Car, we have started cutting open every single Oil Filter during a routine Oil Service as part of our auto repair inspection.  The pictures here show the IMS bearing taken apart and the insides explored.  This IMS bearing came out of a 2002 Porsche 911 cabriolet with 45,000 miles.  The customer decided to inspect the IMS bearing after the result of the filter cutting showed signs of metal debris.

The 1st picture is of the IMS bearing with 2 slits in the outer race.  I took a cut off wheel and performed these cuts.  Do not perform this at home without all the proper safety equipment and training.  This is the size of the IMS bearing and it can fit in the palm of your hand.

The 2nd picture is the IMS bearing being separated.  You can see the inner ball bearings have fallen out as there is nothing supporting them anymore.  At this point you can start to see the innards.  The IMS bearing has an Outer Race, which is cut in half and they now look like half moons.  This is a dual row IMS, so it has 2 rows of 8 ball bearings making a total of 16 ball bearings.  You can then see the cages which hold the ball bearings apart from each other.  In the very center of the IMS is the Inner Race.

The 3rd picture is the IMS bearing cages.  You can see where each ball bearing fits inside around its circumference.  The bearing cage is made of a tin like metal.  The cage is not very strong because there is very little if any load applied to it.

The 4th picture is one of the half moon outer races and only 6 of its ball bearings.  You can see the engine oil pooling on the bottom.  Within that pool of oil you can see very small silver metal flakes that appear to be silver glitter.  These small metal flakes are being created by this IMS bearing failing.  And the metal flakes when circulated through the engine is prematurely wearing the engine out, ultimately leading to the engines failure.

The 5th picture is the Outer Race half moon.  You can see the double row of races next to each other.  You can see the pitting that is happening in the center of each race going all the way around.  This pitting is the fail point of this bearing and the reason why metal flakes are in the engine oil.

The 6th picture is a mock-up of the inner race, the outer race and 4 of the 16 ball bearings.


The 7th picture is the Inner race.  You can see the double row of races on the inner.  You can also see compared to picture 5 that the inner row of races appear to be much smoother that the outer row.  The smoothness of each race means that its good.  Because the outer race is not smooth the entire bearing is bad.

The 8th picture is the entire assembly separated and shown as each part.  Note: the 2 half moons are originally 1 piece.  I cut the outer race apart making it two individual pieces.

The 9th picture is a brand new IMS bearing ready for installation into the engine.

If you have any further Porsche IMS bearing failure questions and need auto repair service in the San Diego / Encinitas area, please call Niko at Charlie’s Foreign Car Service 760-753-4969.  We’re located in Downtown Encinitas, 751 Second St. 92024