IMS Service KIT

Porsche IMS Bearing Failure – What You Need to Know

If you own a Porsche Boxster, Cayman, or 911 from 1999 to 2008, you’ve probably heard the words IMS bearing failure. It’s a common concern among Porsche owners – and for good reason. When an IMS (Intermediate Shaft) bearing fails, it can cause serious engine damage and costly repairs. But the good news is, with early detection and the right replacement, it doesn’t have to be a disaster.

What causes IMS bearing failure?

The IMS bearing is a weak point in certain Porsche M96 and M97 engines. Over time, the bearing can wear down due to:

Metal fatigue (spalling): the surface breaks apart after years of stress. Poor lubrication: grease can wash away, leaving the bearing unprotected. High load and design limitations: the roller ball design isn’t ideal for long-term durability.

As the bearing breaks down, small fragments of metal and plastic circulate through the engine. If ignored, this can lead to catastrophic failure and a complete engine rebuild.

Symptoms to look out for

IMS bearing wear is usually a gradual process, not an instant failure. That means you can often spot early warning signs, such as:

Metal or plastic fragments in the oil filter or sump plug Unusual engine noises Oil contamination

That’s why it’s smart to change your oil more often than the standard Porsche service schedule and inspect the filter closely. A magnetic sump plug can also help detect early metal particles.

Which Porsche models are affected?

IMS bearing problems mainly affect:

Porsche Boxster (1999–2008) Porsche Cayman (2006–2008) Porsche 911 Carrera (996 & early 997 models, 1999–2008)

There was a switchover in bearing size around 2005:

Smaller IMS bearing: M96 3.6L engines up to #69507475 and M97 3.8L engines up to #68509790 Larger IMS bearing: M96 engines from #69507476 onwards, and M97 3.8L engines from #68509791 onwards

IMS Bearing Replacement Options

When replacing your IMS bearing, you’ll need to know your engine type and size. At Design 911, we supply both:

Open IMS bearings – for engines currently being rebuilt Closed IMS bearings – for engines still assembled (requires a special boring tool, available to buy or rent)

Final Thoughts

Porsche IMS bearing failure is a real issue, but it doesn’t have to mean the end of your engine. With regular oil checks, early detection, and a quality IMS bearing replacement, you can keep your Porsche running smoothly for years to come.