DUMF

[Mr_Bo11ox]

I notice theres a lot of hatred for 'dual mass flywheels' on here. I've never had a car new enough to have one, but I've not long sold my mate's 55-plate Astra 1.3 CDTi, and I noticed that it had a regular 'grumble' from the clutch at maybe 10-second intervals when it was idling. When you rev it, it was quiet. It was an unusual noise and not one i've heard on any of my old shitters.

 

The car is gone now like, but does that sound like a DMF problem? Do these cars have a DMF? Whats the cure and how much does it cost?

[chester drawers]

Not familiar with the Corsa, but Valeo do kits to convert to a conventional arrangement

 

http://www.valeoclutches.com/Products/C ... on+Kits/45

[warren t claim]

Some DMF cars are somewhat undriveable when they have been converted to a solid flywheel.

[Station]

Just took a flywheel out to replace with a lighter one. I can barely lift the flywheel, it's about 30kgs. All the TDi's apparently need these as they're so powerful and high on torque, apparently the crank is 'unbalanced' with four cylinders. Think they're like those spinners you see on alloy wheels.

[red5]

A lot of the DMF failures are down to driving style more than (admittedly) poor materials/design. They really do not like extremely low engine speeds at all, which a lot of people mistakenly think is 'economical' driving. Beware of some kits which leave you with terrible driveline resonance/vibration - worse than the pain of replacement.

[dieselnutjob]

Some DMF cars are somewhat undriveable when they have been converted to a solid flywheel.

Not my Peugeot 806 HDI.

The Valeo 4 part clutch kit has been fantastic

Previously the 806 had destroyed two DMFs (the original and the replacement)

The only downside I have noticed is a very slight loss of refinement at full throttle. The engine is slightly harsher than it was before. No one else has noticed it though.

[Vin]

I always thought a flywheel was a flywheel was a flywheel, but you learn something new everyday

 

[Pillock]

55-plate Astra 1.3 CDTi,

Bet that was a barrel of laughs to drive!

[Tayne]

.

[Milford Cubicle]

Is it new enough to have a dual mass failwheel?

[dieselnutjob]

If I come off the throttle, but leave it in gear, as it rolls to a halt it doesn't do it.

Is that because the engine just stalled

 

But if I put in neutral whilst still moving I get a slow vibration which slows down with road speed

If you are in neutral then I don't think that there is any relationship between road speed and flywheel speed, so I think nothing to do with the DMF.

 

It has to be a rotating component that's final drive side, such as the diff (unlikely on a front wheel drive), drive shafts, brakes or a wheel bearing.

 

You could if you really need convincing put it in neutral and turn the engine off and then coast to a halt, but be aware that you will loose brake servo assistance and power steering so do it in a deserted place like an industrial unit on a Sunday or something.

[red5]

My Audi (1.9tdi) has an odd vibration when costing in neutral.

If I come off the throttle, but leave it in gear, as it rolls to a halt it doesn't do it.

But if I put in neutral whilst still moving I get a slow vibration which slows down with road speed, almost as though something is catching as the wheels go round.

I do drive around town at 1100-1500rpm.

 

Is this a sign of impending DMF-doom?

When you select neutral whilst coasting does the engine speed drop to normal idle or hover around the 1100 rpm mark ?

[Tayne]

.

[Pete-M]

I used an A6 V6 2.5 TDi for a while, when the DMF failed on that it started as a weird rumble, then a vibration occasionally, then big vibration at certain engine speeds.

 

Then it got changed. Wasn't cheap.

[oldford]

They can fail in an alarming manner, this one stopped the engine:

 

 

[dieselnutjob]

on my 806 the first DMF failed with the only symptom that there was a scraping noise when the clutch was half depressed (like at the biting point).

I think a lot of people would have just ignored it.

Luckily I didn't ignore it and when I took the transmission off (which is a horrid job on an 806) I found that the DMF failure was allowing the clutch cover plate to move back to the point that it was chewing its way through the transmission housing. There was a circle of missing aluminium around the input shaft. This is what was causing the scraping noise.

The second DMF (made by LuK) lasted less than two years before the clutch started slipping on full power. This caused us to miss a family holiday that I had planned because I didn't want to tow a caravan to France with a slipping clutch.

DMFs are a fine idea in principle, but they just don't seem robust enough.