The Porsche IMS issue - check your bearings!

The IMS (intermediate shaft) bearing issue has been a significant concern over the years for many classic Porsche owners, particularly for those with cars with either an M96 or M97 engine, and likely produced between 1997 and 2008. It’s affected certain models of Porsche, including the 911, 996, 997, 986 and the 987. 

So what is an IMS bearing, and what is the problem? Well, the IMS bearing supports the intermediate shaft, which in term drives the camshafts. Due to its sealed design, the original ball bearings used can sometimes fail prematurely, leading to potential engine damage if not addressed in time.

One key factor in the IMS bearing problem is that it’s often difficult to tell when the bearing might fail, which makes the issue an unpredictable one. Some bearings last the lifetime of the car, while others fail prematurely, sometimes even with minimal mileage. As a result, many Porsche owners opt for proactive replacement or upgrades to avoid the risk of catastrophic engine failure. Depending on the model and age of the car, this may be an easy replacement, or it may require more work in terms of disassembling the whole engine.

The exact cause of the failure is currently not known, but it has been suggested that it could be due to quality issues, poor lubrication or perhaps the elevated temperature of the car’s engine. The deterioration problem seems to stem from wear and tear on the bearing, exacerbated most likely by a lack of lubrication. Over time, the bearing can degrade, causing debris to enter the engine, which can result in breakdowns or that unwanted nightmare of a total engine failure.

The signs of IMS bearing failure can be subtle. While some symptoms (such as metal debris seen in the oil, or engine noise) can indicate early failure, the issue often presents without warning, leaving owners vulnerable to sudden breakdowns. Because failure often occurs without warning, regular maintenance and inspections are therefore critical. It’s recommended to have oil filters inspected for debris at regular intervals, as this can be an early indicator of bearing wear - but not in every case, unfortunately.

Several aftermarket solutions are available to address this issue. These upgrades typically involve replacing the factory-installed bearing with a more robust design, such as a ceramic bearing or even a completely redesigned bearing system that eliminates the weak points of the original. Many car specialists also recommend converting to an oil pressure-fed plain bearing system. Ultimately, it’s best to chat to a specialist who can advise you about your particular car.

It’s clear that taking steps to address the IMS bearing issue is vital for Porsche owners of affected models. While not every vehicle may experience bearing failure, the potential consequences are severe enough to warrant proactive measures being taken, such as replacing the bearing with an upgraded solution.

Ultimately, any preventative action you can take sounds like a wise investment for the long-term, as trying to fix the problem after it has happened could be very costly indeed…