Question on Dual Mass Flywheel

[berty987]

Calling toolpants or any service techies out there. I have a 2005 model boxster (3.2 s)currently in with an indie for clutch replacement. The car has covered 26,000 miles and symptoms were high biting point and clutch slip when pulling away from standstill when driving enthusiastically. The indie has taken the clutch apart and advised that the dual mass flywheel needs replacing !!! The clutch doesnt seem to be worn out , and there is no scorring on the flywheel , so they put the slip down to a weak pressure plate and the flywheel. They are suggesting the flywheel needs replacement becuse the tolerance is out on the amount of slack between the two plates. anyone know anything about testing the dual mass flywheel (same as 986 boxster) or what the tolerances are ? Is it normal to replace the flywheel with a clutch or are they being over cautious ? Need to confirm tomorrow so any replies welcome. thanks

Edited April 25, 2007 by berty987

[pjslowik]

Calling toolpants or any service techies out there. I have a 2005 model boxster (3.2 s)currently in with an indie for clutch replacement. The car has covered 29,ooo miles and symptoms were high biting point and clutch slip when pulling away from standstill when driving enthusiastically. The indie has taken the clutch apart and advised that the dual mass flywheel needs replacing !!! The clutch doesnt seem to be worn out , and there is no scorring on the flywheel , so they put the slip down to a weak pressure plate and the flywheel. They are suggesting the flywheel needs replacement becuse the tolerance is out on the amount of slack between the two plates. anyone know anything about testing the dual mass flywheel (same as 986 boxster) or what the tolerances are ? Is it normal to replace the flywheel with a clutch or are they being over cautious ? Need to confirm tomorrow so any replies welcome. thanks

I believe to test the DMF you grab the outer part of the flywheel and twist it. It should be able to move, with some resistance, 15* in either direction and return to center upon release.

You should have taken it to a dealer for warranty repair instead if the independant mechanic. Now they may not cover it being it was disassembled.

[PTEC]

There is a technical bulletin on testing procedures for the DMF. The test is pretty much to lay it down and twist it and see how much it twists and if it returns. I might take your chances with your flywheel. At worst the flywheel may chatter but I have seen some seriously bad flywheels that didn't make a single peep. Porsche makes a repair kit that includes the disk, the plate and the throwout bearing. I would replace all of this stuff and see where you're at after that. They're probably recommending the flywheel just to be safe and cover their arse.

Also FWIW, a dealer won't cover the DMF for a slipping clutch.

[pjslowik]

Also FWIW, a dealer won't cover the DMF for a slipping clutch.

I don't think they have much choice. If there is no evidence of abuse, and the part is defective, there's no reason to deny warranty coverage. I have had mine replaced under warranty. I also have a 99 Passat that has a DMF and original clutch with 115,000 miles, and they perform perfectly. Both cars have the same transmission BTW. If your denied by one dealer, try another or squawk to the factory rep.

[berty987]

Spooky world that you have a '99 passat with 115,000 miles as a second car.....so do i , with the same mileage and on original clutch too. I wouldn't take the car to porsche because of the warranty clause on wearing items and also if unsuccesful in the claim it would be a crippling 2000 pounds for the work (this is costing just under 900 including the DMF and clutch ). I spoke with tech support at LUK (DMF suppliers/ mfrs) and they quoted there is no specific tolerance for the amount of movement between the two parts of the flywheel. Though the TSB suggests 15mm is allowable LUK suggest that up to 30mm is common depending on the application to which the DMF is fitted. It will be hard to prove the car has not been abused , since clutch slip at 26,000 miles is very unusual , and i purchased the car with 20k on the clock , so i have racked up some fair mileage. What is interesting is the guy at LUK said that the two parts of the DMF are separate and there is a friction section sandwiched in between. This is sacraficial in the event of an excess load being placed on the gearbox or engine and can itself cause clutch slip symptoms if damaged. The DMF can also only be truly tested if it is seen in a dynamic state , so the bench test is somewhat limited. Are you suggesting in your post that the Passat DMF and Porsche item are actually the same device ? There seem to be very different capabilities and horsepower requirements between the two engines.

Edited April 20, 2007 by berty987

[pjslowik]

Spooky world that you have a '99 passat with 115,000 miles as a second car.....so do i , with the same mileage and on original clutch too. I wouldn't take the car to porsche because of the warranty clause on wearing items and also if unsuccesful in the claim it would be a crippling 2000 pounds for the work (this is costing just under 900 including the DMF and clutch ). I spoke with tech support at LUK (DMF suppliers/ mfrs) and they quoted there is no specific tolerance for the amount of movement between the two parts of the flywheel. Though the TSB suggests 15mm is allowable LUK suggest that up to 30mm is common depending on the application to which the DMF is fitted. It will be hard to prove the car has not been abused , since clutch slip at 26,000 miles is very unusual , and i purchased the car with 20k on the clock , so i have racked up some fair mileage. What is interesting is the guy at LUK said that the two parts of the DMF are separate and there is a friction section sandwiched in between. This is sacraficial in the event of an excess load being placed on the gearbox or engine and can itself cause clutch slip symptoms if damaged. The DMF can also only be truly tested if it is seen in a dynamic state , so the bench test is somewhat limited. Are you suggesting in your post that the Passat DMF and Porsche item are actually the same device ? There seem to be very different capabilities and horsepower requirements between the two engines.

On my DMF, when tested, it would not spring back. Also, my clutch and pressure plate were only engaging in the outer half of the diameter. I never heard of this before. I was just out in my 99. I bought it new and do all the work myself. I really enjoy it and am glad I decided to use synthetic since new even though it was not required at the time. I love that turbo motor. I also have an 04 Passat GLX V6 4Motion and an 87 GLI with 240K miles.

I doubt the DMF and clutch are the same in the two cars, but I know for a fact that the 5 speed is the same as the Passat/A4 5 speed, except for ratios.

I see you didn't buy your Porsche new. I regret buying mine new with 300 miles on it. I usually don't buy cars that have been driven. I don't know how it was treated in those critical first miles. Also, I made the mistake of letting a service manager take the car to try it overnoight after an engine replacement. Might just be consern about nothing.

Good luck with your car. Get it right no matter what the expense so you can enjoy it.

[berty987]

The indie that have the car seem pretty thorough and seem to know their stuff. I've decided to get the DMF replaced and follow their reccomendation, the part is minimal in cost compared to having the whole transmission out again in a year or so if the DMF fails. Luckilly no signs of the dreaded RMS leak and they have advised if it aint broke dont fix it, so although an unexpected additional cost , its still cheaper than OPC prices and i have peace of mind. to be honest when i bought the clutch I did consider going the uprated route with lightweight flywheel, but decided against as I want to use the car for touring and road use rather than sprints and track.

Since VW/ Porsche have their hands in each other's pockets I'm not surprised that the transmissions are similar if not the same on the 2.5/2.7 and Passat/ A4 . Certainly porsche seem to list a lot of special VW tools for maintenance tasks.

Regarding Oil on the Vw , I've been using synth Castrol GTX magnatec since I heard of the sludge problems caused by non synth oils on the turbo engines. Like you the Vw is now old enough to get my full attention and I do what i can on the car myself. With its current mileage the top of the engine is a little tappety but I'll probaly have the cam covers off to inspect if it gets any worse. I'd love to tinker on the Porsche but the stakes are higher if something goes wrong and people like to see official reciepts for work when you sell it on.

So money on the table and wait for the call its all fixed ready for collection , then off to enjoy "the best summer ever" we are promised this year !!.

[pjslowik]

Berty, what happened with this?

[berty987]

I picked the car up last night from the workshop and spoke to one of the people in charge while reviewing the parts. Really strange , the clutch friction disc still has plenty of material on it , the pad sections still clearly visible on both faces and no signs of bad scoring , just one small piece missing (about the size of a jean rivet , but only about 1mm deep and friction material still underneath). The pressure plate is also in good nick , no broken fingers and only discoloured where the friction material sits on its surface not blued or straw colour suggesting its got excessively hot. The fingers of the lutch cover are blue in colour but not sure if this is how they look after treatment or if they have become hot. The DMF is the same story, no surface damage , just slightly discoloured wher the friction surface sat against it. I tried the twist test and the two halves of the DMF do move about 20-25 mm with little effort , then it just locks up and you can definitely feel very strong resistance. The movement appears to be free travel though, as the rotation isnt self returning over the first 25 mm. The clutch pedal doesn't seem to have a biting point any lower than before either , so i'm still confused why the clutch was slipping when you pulled away with some urgency. This was the only time i felt the clutch slip and it was severe (3-4k revs and in gear with no movement , just piles of acrid smoke from the engine vents and under the car !). If it had happened only once , then i could understand the clutch may have been hot already , or prerhaps glazed. I havent tried any grand prix starts since getting the car back and the mechanic tells me there is no adjustment in the clutch so the biting point must be normal , but it feels about half way on pedal travel.