57,000 miles and so far so good. This pool, however, doesn't account for the driving style of the various owners. It would be very difficult to quantify that stuff to reach any reasonable conclusions.

08 997.1 C2S 46K miles - no IMS but RMS replaced @ 45K miles.

It's a more robust version of the factory part - uses special hardened bearings manufactured with a process that was not available back in the day. Also beefed up nuts, bolts , etc.

05 C2S. No IMS failure.
Thrust washer failed at 36,000.
Destroyed engine.
Porsche replaced engine under CPO.

So, the poll on htis site so far is about 7% failure. I'm sure Porsche has data as to what the risk of failure is for a car with a given build date. Lemme guess - not published?

I think we probably need more data points... there are a lot more cars on the board than this. Also I suspect that 7% (or whatever number this settles to) is really just a starting point. As Edgy says above, driving style and other mitigating circumstances could drive the failure rate up or down. Also I'm sure some cars are more prone to failure. All these factors mean that this is far from a scientific test.

I have noticed that everyone who wrote in with a failure has yet to write in the details of the car and the circumstances etc. I'd love to see that information to come in so we can get a sense of how these failures actually happen.

Any idea what sort of driving style would push those engines with a higher chance of failure over the cliff?

garage queens that are driven 5 miles a week at 1500 rpm around town on sundays for starters.

As someone who does a lot of statistics for a living, I would very much dissuade you from making sweeping generalizations from this data. Your sampling is very skewed towards people with the problem (more likely to answer) as well as not having accountability (only 1 real person who had the IMS fail has posted).
Also, you have a tiny dataset without any ability to get decent margin of error.

My personal estimate is that it is well below 1%, even for 2005 owners and is highly correlated to driving style and frequency like Edgy mentioned.

2009 997.2 C4S - No failure

2007 997.1 C4S w/ 33K Miles - No Failure

You don't work for Paul Ryan then! ;)

of the 5 users that reported failures:

1 was not a 997- shouldn't count
2 users have been on the board for a long time (years) and they do own 997s
2 users have been on the board a long time (years) and no notes on thier profile as to which car they own

I think for the time being we can assume that there are at least 4 legit failures on this board since there is no compelling reason to lie for those long time members.

again, this isn't a very scientific survey of course (I also conduct consumer research as part of my job and this test would never fly as anything but anecdotal). I'm interested to hear even anecdotal evidence.

`06 C2S w/27k miles and no issues.


Update: 09/05 build; 30,257 miles

997 2005 C2, 45K miles, no IMS problem, no other engine issues