How long does it take once an IMS starts to go?

[Overdrive]

Forum threads tend to make the issue look way more frequent than it really is, so I can understand the frustration. I guess I read them in relative comfort since I had the retrofit done going on 2 years ago, and while I know that's not bulletproof, it's at least better than it was, and I can drive the car without being stressed out and worried like I was for the first year I had it.

[southernstar]

Yes, they do tend to create paranoia - although this thread shows many more owners who have had zero problems with their IMS bearing in spite of some significant mileage. At one point alarmists were making it seem as if every Boxster with an IMS had a ticking time bomb for an engine - and no doubt this has fueled the incredible depreciation that all Boxsters seem to have suffered over the last couple of years.

Fortunately, the numbers released by Porsche in the course of production for the class-action suit puts things in perspective: in the worst case scenario, a single-row bearing car in California, only 10% of the cars are apt to suffer a failure of the original IMS bearing. Inotherwords, you have a 90% chance of it not happening even if you do nothing.

In the best case scenario - a double-row bearing, you have much less than a 1% chance of the original IMS bearing failing. Indeed, the reliability of the dual-row bearing seems to have been the greatest evidence that the plaintiff's had that the single-row bearing, with its much higher failure rate, was designed negligently and as a result the reliability of the cars so effected fell below the standards that one would/should reasonably expect in a modern performance car (for over a century the courts have ruled that there is an implied warranty that any product is at least reasonably suited for the purpose for which it is intended).

The good news, as I see it, is as follows:

1. We now have some real numbers upon which to base our assessment of the risks and the cost/benefit analysis of any upgrades/repairs.
2. The numbers establish that failure of the IMS bearing is by no means a given and, in fact, is unlikely (and extremely unlikely in the case of a dual-row bearing).
3. IMS bearings (up until the final, larger bearing) can be replaced without an engine tear-down.
4. If replaced at the same time as a clutch replacement, very little additional labour is required.
5. The cost of the upgraded bearings varies from quite low for the Pelican bearing (suitable for single-row replacements, less suitable for dual-row as it downgrades to a single-row with a spacer) to a high of $649.00 for the LN engineering ceramic.
6. While there is an additional incentive for owners of cars with single-row bearings to be proactive and replace the bearings without waiting for a required clutch replacement, nevertheless, the improved resale value (and peace of mind) should make the decisioin more palatable for those who consider an 8-10% risk too high.
7. Thereafter, upgraded bearings should be able to be viewed as a maintenance item which thereafter will only need replacement when the clutch is also replaced.
The LN 'solution', although more expensive, may even be a permanent solution (as claimed).

I can't help but believe that the hysteria can now die down. Many performance cars (inlcuding many highly soft-after Porsches such as the 911SC) have had mechanical issues that require upgrades to the engine. Very few of those who risk waiting on upgrading the IMS bearing will suffer a failure. What's more, once upgraded the owner can seemingly have confidence that the problem has been overcome. This should, over time, lead to an improvement in the resale value of these otherwise incredible and highly desireable cars.

Cheers!