IMS Bearing

Virtually everyone who owns a 996 or 997 (Carrera 2/4/S/4S), 986 or 987 (Boxster/S), or 987C (Cayman/S) has heard of the IMS Bearing failure and many fear it so much that they barely drive their cars.  While the bearing certainly can fail, based on my experience the rate of failure is far lower than many would think from their online research.  I can count on one hand the number of catastrophic failures that have been in my shop and still have a couple digits leftover.  I have actually seen more cracked cylinder heads than IMS Bearing failures.  It must be noted that we use high quality Porsche approved motor oils and the correct OEM oil filters in our servicing.  We perform complete services for our clients as opposed to blindly changing out a few parts.  We also encourage oil services at 5K mile intervals or at least once per year on these models.  Proper servicing of the cars may not eliminate all problems, but it sure seems to help minimize them.

The RMS issues are often confused with IMS issues, so let us clarify the difference.

RMS – is the Rear Main Seal or flywheel seal of the engine on the crankshaft.  Although many engines were replaced under warranty for leakage at the RMS area this is typically not a catastrophic failure.  The engines that were replaced under warranty for RMS leakage were measured for proper location of the crankshaft and cradle within the case.  If they failed the prevailing test of the day then the engine was replaced.  If they passed, then they got a new rear main seal of the day.  I do not have enough fingers and toes to count the number of revisions to the seal, seal installation tool, and accepted case measuring techniques there have been over the years.  After all that, they still have a tendency to seep on most engines.  We recommend replacement or updating of the RMS and case bolts at the time of clutch or IMS bearing replacement.

IMS – refers to the InterMediate Shaft Bearing on the flywheel side of the engine, behind the IMS flange, and inside the intermediate shaft.  This is a single or dual row ball bearing which supports the intermediate shaft on a centering journal in the IMS flange at the flywheel side of the engine.  The intermediate shaft is driven by the crankshaft via chain directly over the IMS bearing and the IMS drives the bank 1 camshafts via chain at this end too.  The intermediate shaft drives the bank 2 camshafts via chain and directly drives the oil pump at the opposite end.  When the IMS Bearing fails or its centering journal breaks off the result is often considered catastrophic. Generally you will not only have the failed bearing but collateral damage requiring complete disassembly of the engine to repair. The damage can vary but the debris, which has contaminated the engine from the failed bearing, in itself necessitates a complete teardown of the engine.

The RennShop offers bearing kits and installation services for all 996 and 986 Boxster models.  The 997 and 987 series cars cannot be retrofit without complete teardown.  We only utilize the bearing kits from LN Engineering since they have done extensive research to develop their bearings and we have established history installing these bearings.  This is a critical part of the engine and we are not interested in experimenting on your car.  The following kits are available with installation:

Double Row Retrofit

Single Row Retrofit

Single Row Pro Retrofit

IMS Solution

All installations are done using the proper tooling, with great respect to cleanliness, and proper torquing of all critical fasteners. This consistently insures the best possible results.

To schedule an appointment call 408-727-0911 or email: