Catastrophic Flywheel Failure
 

I have recently had my OEM dual mass flywheel separate into two pieces. The 8 studs holding the flywheel together have all sheared off and the car was left with no drive going through the drive train.

I have found only two other incidences of this occurring on the below posts.

https://www.6speedonline.com/forums/...-flywheel.html

http://forums.rennlist.com/rennforum...-warranty.html

My circumstances were exactly the same. Car drove normally, was parked at a supermarket for two hours, and then on coming out and getting into the car, it would not drive.

I towed the car to my Porsche specialist who said that they had never seen a failure like this before, and that my clutch and FW were in otherwise perfect condition, less normal wear and tear.

I then had the car towed to a dealer, where they did a VAL and over rev report.

Results below:

Note that the operating hours are 180 hours following the last over rev at level 1 or 2, and about 500 hours from the higher levels.

Initially they said that Porsche would not cover the failure of the part in the car for the following reasons;

1/ Out of warranty (997C2S MY 2006)
2/ Not complete Porsche dealer service (I used an indy last service)
3/ The car had been misused evidenced by the below over rev report, and as a result excess stress had been placed on the drive train - implying that these over revs had caused the FW to fail as it has.

Operating hours counter 886.200 h

Number of ignitions at speed > maximum speed, range 1 2907
Number of ignitions at speed > maximum speed, range 2 307
Number of ignitions at speed > maximum speed, range 3 19
Number of ignitions at speed > maximum speed, range 4 1
Number of ignitions at speed > maximum speed, range 5 1
Number of ignitions at speed > maximum speed, range 6 0
Operating hours counter reading at overspeed, range 1 706.900 h
Operating hours counter reading at overspeed, range 2 706.900 h
Operating hours counter reading at overspeed, range 3 393.400 h
Operating hours counter reading at overspeed, range 4 393.400 h
Operating hours counter reading at overspeed, range 5 393.400 h
Operating hours counter reading at overspeed, range 6 0.000 h

I questioned them on the basis that;

1/ If the car had been misused then this would be a common and well known about failure - which it is obviously not

2/ I have owned the car for the past two years, and i have only hit the rev limiter 3 or 5 times

The dealer has now said that they will cover the cost of the flywheel, however i will have to pay them to fit it (and put a new clutch in at the same time - which is fair enough that i pay for). I am not too keen on paying for the dealer to fit a part that has failed, that in my view should not have failed for the life of the car - and indeed has not failed in the majority of other 997s on the road (most probably driven harder than mine has been).

From the research that i have done, the over revs shown are nothing to be too concerned about, and actually you would struggle to find a second hand manual 997 with no over revs. Some input from the knowledgeable people here would be appreciated.

I am not quite sure what the single 1 values mean in ranges 4 and 5???

Thanks for your comments.

many people are posting overrev report here before buying.
all overrev report show multiple stage 1 and 2. it's a porsche... ment be to driven...
and some show 1 overrev at stage 3,4,5 and 6. which is simply impossible...

so in your canse, the stage 5 overrev is impossible.
the stage 4, maybe..

when I did my PPI at a porsche dealer (different from the porsche dealer selling the car) they mention that they only care about range 5 and 6

and by looking at the time they occur, your car probably had a little electronic bug at 393.400h where it registered a single overreg at stage 3,4 and 5. so in fact you have 18 overrev at level 3, and nothing over that.

my c2s 2006 had 10 overrev stage 3 when I bought it and still covered by CPO at purchase.

Sorry to bump into the conversation like this. I have seen these over rev reports
What does a stage 3,4 ,5 etc mean?
Can someone explain this to me, I thought previously it meant the gear you overreved in
Tx

I don't know the exact RPM numbers...

red line is at 7400 RPM
so a stage 1 overrev could be from 7400 to 7600 RPM
a stage 2 overrev could be from 7600 to 7800 RPM
a stage 3 overrev could be from 7800 to 8000 RPM
...
...

again, RPM numbers are wrong in this, it's just to explain the concept...

Tx that's what I thought

I don't think the warranty can be denied if you didn't serviced your car at the stealership as long as the maintenance was performed.

Melbourne Florida or Australia? Might have different warranty regs if in Australia.

You are right. Where are you from?

Melbourne, Australia

oh, ok. Maybe they have different policies and/or laws governing these kind of things.

Might be a good time to consider installing an lightweight flywheel. Maybe they could just credit the cost of the stock replacement toward the cost of the clutch assembly to defray some of the cost.

I wouldn't install a light weight flywheel unless needed for racing purposes. I have driven a car with light weight FW and they make weird rattling noises. The stock FW was made that way on purpose, to dampen engine vibrations etc. Any change introduces other potential issues.

Nothing in the over rev report is unusual . The 4 and 5 never happened because the time interval of 1 ignition isn't a meaningful interval. 3 wasn't long enough igniton interval, nor a high enough rev, to damage the flywheel. So, as you say, the rev report doesn't suggest anything with regards to prior abuse. As for the free flywheel, car is out of warranty so the dealer isn't obligated to do anything. Seems to me they are being more than fair as no part of any car is guaranteed never to fail and while the mode of failure in your case is rare having to replace a flywheel while replacing a clutch does happen.

update
 

Flywheel replaced by Porsche dealership as a goodwill / warranty item. I had to pay for fitting and elected to install new clutch at the same time.

Although the part should not have failed in the first place, and was clearly a manufacturing defect, i am not dissatisfied with the outcome.

Car is now back on the road and driving as well or better than it ever has.