[southernstar]

So Sean, for you the 'much less than 1%' hasn't provided some additional comfort in making that decision? To me, the most important aspect of the class-action suit IS the release of numbers concerning the respective failure rates of the dual-row and single-row IMS bearings. Remember, this was obtained from Porsche during the discovery process and the relative reliability of the dual-row IMS bearing was actually used by the plaintiffs in establishing their claim that the single-row bearing was negligently designed, rendering the engines unsuitable for their intended use. Porsche had every reason to inflate those numbers as the difference in failure rate - espeically considering the fact that the dual-row cars were older (and typically would have higher mileage) than the single-row cars, made the case against the single-row bearing a virtual slam-dunk for the plaintiffs.

Put it this way, a reported failure rate of much less than 1% is very low in the circumstances. Heck, it is still very low even if we substantially increase 'much less than 1%' TO 1%, to take into account those who never brought them into a Porsche dealership, or attempted to get compensation after failure. Consider the following:

1. The dual-row bearing cars are now all at least 11 years old; some (manufactured in 1996) are now 17 years old!
2. As a sports car, one would expect that many would have been subject to more 'spirited' driving than the average sedan; indeed, unlike most sedans, a significant percentage would have been used for track-days, autocross etc.
3. The reported rate is not limited by mileage - i.e., it would include cars with 200,000 miles or more! This is not just theory, we know of engines that have gone longer than that without IMSB failure.
4. Again, as the reported failure rate includes all vehicles, it also includes vehicles that were inadequately maintained and where, for example, the oil and filter were not changed regularly.

Considering the above, can anyone really say that the failure rate for the dual-row bearing is excessively high? Certainly, the lawyers for the plaintiff didn't think so; in fact, as mentioned above, they used that low failure rate as evidence of the difference between a well-designed and a negligently designed component.

Can a dual-row bearing fail? Yes, but so can the major engine components of any engine. For some, even this low failure rate will be enough of a concern for them to spend significant money to replace something which is likely not in need of replacement. To make an expensive prophylactic repair on what is now a relatively inexpensive car.

Let me tell you a story about a conversation I had recently with my Porsche factory-trained indy mechanic. I am taking a road trip in my 2000 2.7 this summer and, as I will be travelling to the Canadian east coast - an area that is not exactly overflowing with Porsche dealerships/mechanics, was inquiring about some potential repairs to be done as a prophylactic. In particular, as my car now has about 57,000 miles, I was considering replacing the water pump with a new Porsche facory part. I was already having the serpentine belt replaced and in the process, he had already checked out the pump and found no signs of leaks, or noises or play in the pulley consistent with pump bearing failure. When I asked if I should replace it anyway, in view of reported problems with these units, he said:

Yes, I have replaced a number of failed water pumps on these engines, although generally with higher mileage. Of course, I have also seen transmissions fail - would you like me to replace that too?

Brad