Bear with us: it’s time to talk about IMS bearings
Updated: May 7
What is the Intermediate Shaft Bearing, and what cars does it affect?
Replacing the IMS bearing is a preventative fix on M96 and very early M97 motors. We do it because when it fails, it fails without warning.
Porsche designed this bearing to be sealed. As anyone who’s ever spent time on a skateboard knows, no matter how good a roller bearing seal is, eventually the grease will get out. The bearing failure occurs when the engine oil washes out the bearing grease, but then doesn’t provide enough continued lubrication to keep the bearing from wearing. Cars with high mileages on original bearings seem to have been lucky enough to have adequate oil flow to prevent this from happening. Replacement bearings from reputable vendors like LN engineering have been specifically designed to reliably function in this environment and offer peace of mind motoring.
The following is a basic guide to the process to safely replace the bearing on an early 986 Boxster S. The car is a one owner example with approx. 25k miles, and has a 5 chain variant of the M96 engine displacing 3.2 Litres. Pre work: Pull the drivetrain from the vehicle, and separate transmission and flywheel assemblies from the engine.
Rotate the crankshaft to cylinder one top dead center (TDC). Lock the timing using the camshaft lock tool and crankshaft lock.
Remove the chain tensioners
Remove the IMS bearing carrier and intermediate shaft seal.
Assemble puller tool
Slowly pull out bearing
Prepare the new bearing. This IMS Retrofit dual row bearing replaces the OEM bearing with custom ceramic hybrid dual row bearing.
Install the alignment plate to help guide the bearing
Assemble driver tool
Begin to drive the new bearing into the intermediate shaft
“So much of this process is about using feel. Knowing how and when to apply torque to a wrench, versus applying horsepower to a wrench.” – Jordan
10. Listen for clicks, and remove the driver tool to check progress
11. Once the IMS bearing is seated and flush, install the carrier.
12. Torque the 3 bolts evenly, and use a sealing agent before replacing the center bearing nut. Then you’re done!