In recent years, failure of the Intermediate Shaft Bearing (IMS) has been widely reported related to the Porsche Boxster, 911/996 and 911/997 engines. Although this encompasses both a single row bearing and a double row bearing design, failures have been reported causing catastrophic engine failures. Exact failure rates have not been officially reported by Porsche, but information from Porsche indicates a failure rate of less than 2%. Although this failure rate is relatively low, failures can lead to significant engine damage.
The intermediate shaft bearing is designed to support the intermediate shaft at the end of the engine where it mounts with the transmission (flywheel end). The bearing is a sealed ball bearing design that has utilized both a single row and double row design. Early models 1997–1999 made use of a double row design, while 2002–2005 utilized a single row design. Earlier models (Boxster and 911/996) were of a single row design while later models use a double row bearing with a larger center. The later design used since the later half of 2006 (Boxster 2.7, Boxster S 3.2, 911/996 3.4 and 911/996), are improved and have a much lower failure rate. It is worth noting that this later bearing cannot be changed without a complete engine rebuild. Earlier models using the single row bearing can be upgraded and serviced while the engine is intact and still within the vehicle. The engine must be separated from the transmission to complete this repair.
Regardless of which bearing design is in your Porsche, the root cause of failure is contamination in the oil (dirty or old oil). The bearing can also be degraded due to external oil leaks contaminating the bearing from the outside. When the bearing begins to fail, metal particles and other materials are circulated through the engine oiling system causing engine mechanical failure. Bearing failure may also lead to timing chain failure and immediate engine destruction. Another failure related to the IMS is the mechanical failure of the bolt that holds the intermediate shaft assembly. The later bearing design makes use of a larger center bolt and as such this type of failure in post 2006 models is far less frequent.
You can check for early warning signs of mechanical failure. One way is to listen carefully to your Porsche engine when you first start the vehicle cold. If you hear a rattle noise that goes away after the vehicle runs for a few moments, this can be an early sign of timing chain or bearing rattling in the engine case. The second is to change your oil regularly (5,000 to 7,500 miles) and cut the filter to inspect for any metallic debris or contamination. Lastly, if you are removing the transmission to replace the clutch or other similar service, remove the cover from the IMS bearing and visually inspect the bearing and the bearing race. We always recommend that you bring your Porsche to the experts here at German Auto Center and we will be happy to perform your service and inspect your filter.
Engage in regular Porsche, Mercedes Benz, BMW, Volkswagen and Audi service in Austin to ensure your German engine is running smoothly. German Auto Center provides knowledge and expertise for those seeking Porsche repair in Austin. If you have any questions, simply come by and visit Austin German automobile repair experts at German Auto Center and we will be happy to assist you.