Do I need to worry about my Porsche IMS bearing failing?

So you purchased a Porsche and didn't do a PPI (pre-purchase inspection). You've gone onto Google or the Porsche forums and are now losing sleep over the potential for an engine failure. Or maybe you already own one and just found out about all of the potential issues or problems with Boxster, Cayman, or 911 996 and 997 engine. So what are your choices?

Now that you know there are issues with the Porsche intermediate shaft bearing and cylinder bore scoring in M96 and M97 engines, there are steps that can be taken to reduce the likelihood of having an engine failure. 

It’s hard to attach a figure on how long the original IMS bearing will last. It is equally difficult to determine what the true failure rate is for these bearings, as the 8% rate revealed during the Eisen class action lawsuit was for failures that occurred during the warranty period. Likewise, there are no figures when it comes to cylinder bore scoring, but we know that the 3.4, 3.6, and 3.8 liter engines suffer from failures at any mileage, just like an IMS, and no model is immune.

Many intermediate shaft bearings that are replaced may appear to be in good condition, but for every bearing that looks ok, we can easily find a bearing that is in very poor condition, right on the edge of failure. If you find debris in the filter (or on the magnetic drain plug, if you have one installed), you have to realize that the bearing itself has to have deteriorated enough to first damage the grease seal which then allows ferrous debris to be ejected from the bearing. In most cases, once you discover the IMS bearing is failing or failed, it is too late to replace it. 

With the knowledge that the IMS bearing should be replaced proactively, you can have your IMS bearing changed out with an IMS Retrofit or IMS Solution. If you have a MY06-08 with the non-serviceable intermediate shaft bearing, there isn't much to be done proactively other than to remove the grease seal off of the original factory IMS bearing. This allows the engine oil to properly lubricate the bearing and also why IMS Retrofit bearings do not have grease seals on them.

If the IMS bearing fails, you basically have three repair options: install a used engine, purchase a replacement engine from Porsche, or having your existing engine rebuilt.

The reasons why you cannot replace the intermediate shaft bearing in an engine that has suffered an IMS failure is two-fold. First, the failed bearing usually cannot be extracted, and if it can be removed, the intermediate shaft itself will be damaged to the point that it will fail, even when a new bearing is fitted. Second, the debris from a failed IMS bearing has to go somewhere. Most of it will end up in the filter but this foreign object debris will contaminate the rest of the engine in the process. Best case it causes increased wear, or worst case, it leads to catastrophic engine damage.

Failure concerns aside, the best thing you can do is drive your car as Porsche intended. Once up to operating temperature, do not hesitate to drive it hard and go to redline. In fact, trying to keep your RPMs up (at least above 2500-3000 rpm) will greatly improve the longevity of the IMS bearing. We're not going to go into the dynamics of ball bearings, but suffice it to say, ball bearings last longer when they are spun faster. That’s why Porsche put a larger diameter bearing in engines starting with the 2006 model year as this increased the surface speed for the balls and races.

It is equally important that you maintain your Porsche well. This goes beyond following factory recommendations. Basics include installing a magnetic drain plug and changing your oil every 6 months or 5,000 miles, whichever comes first. While changing your oil, it is important to open up the oil filter to inspect the pleats for any debris that might indicate an IMS or some other problem. It is best to use a synthetic 5w40 oil with increased anti-wear additives, like Driven DT40. DT40 also has very high levels of moly friction modifiers, higher than any Porsche approved oils in fact, and provides the best protection against cylinder bore scoring (among other known issues and problems associated with M96 and M97 engines). 

If you are unsure what maintenance your Boxster, Cayman, or 911 996 or 997 requires, seek out the advise of a Porsche expert familiar with the M96 and M97 engine. A qualified independent Porsche repair shop should be able to provide guidance as to what your car needs to ensure trouble-free operation and reduce the likelihood of costly repairs that can be prevented with preventative maintenance.