and if so, why? why are they not used in petrol motors?

I think some turbo petrols have them now don’t they?

Driving style has a big impact on how long they last, apparently. If you are buying a used car from someone, try going for a test drive and make them drive the car…

No, some petrol cars use them as well. IIRC the Golf R32 uses a DMF.

is the DMFW part of the clutch?

looking at vans and wondering if i should discount anythng with a tow bar on the basis is has probably been used for towing.´, limiting the life of the clutch.

My 10 year old subaru 2 litre petrol has a dmf.

There are lots of ways to kill a clutch beyond towing. The way the driver changes gear and or holds the vehicle on a hill with the clutch will kill it more than the occasional tow.

Clutches are a consumable wearing item, always assume it will need replacing at some point, it’s not something you can plan too much for when buying used vehicles.

looking at vans and wondering if i should discount anythng with a tow bar on the basis is has probably been used for towing.´, limiting the life of the clutch.

Not necessarily, and not by much. My car’s done 100k miles, only about 3k with a caravan on. You seem some people really abusing their clutches on caravan sites, reversing up grassy slopes, but I don’t do that.

You’re more likley to find a trashed clutch where someone’s been habitually riding the clutch in slow traffic or holding it on hills. And you’ll never know until it fails.

Also, a lot of towbars are fitted for towing small trailers to the tip and back. That’s hardly going to ruin anything.

My 2001 petrol volvo had one.. wished it didn’t when i had to pay to replace it!

Another killer of dual mass flywheels is a badly running engine from things like injectors and lambda sensors causing rough or uneven running, coil and plugs in petrols. The extra vibration accelerates the death of the dmf. So if replacing one always worth checking these sort of things to prevent the replacement going the same way.

IIRC the Golf R32 uses a DMF

Really, I’d have thought there’d be no need with a V6, smoother engine etc. My V6 4motion (its predecessor) didn’t have one.

Porsche Boxster has one

More and more cars petrol and diesel are using them, they smooth drivetrain shunts by a massive amount.

I’ve been using them in vans and vehicles since 2003 and had only one failure in that time,(at 15,000 miles from new).

All of my vans have run up 180,000 to 250,000 miles on original clutches and DMF’s with no problems at all. My last Transit could feel a little squiffy at 230,000 miles if I really booted it, so I didn’t boot it often! 😉

My Focus ST has one, but upgraded the clutch to an RS one, which I believe is set up different.

DMFs aren’t so much the issue as poor examples of DMFs – Ford have made some awful ones that kick the bucket at less than 30k. My sprinter managed til 250k before the DMF wore out rather than fell apart and has done another 80k since then without an issue.

Many of people’s tales of woe also revolve around when DMFs were new technology and faults were poorly diagnosed – a failing DMF will bork the starter motor for instance – mechanics and dealers failed to recognise this and tended to treat the symptom – and replace the the starter again and again- rather than the cause. So they’rd be replacing the ancillary parts the flywheel was knackering without realising it was the flywheel was the fault running up £100s of bills and numerous days of repairs on top of the big bill once the fault was recognised.

why are they not used in petrol motors?

the point of them is to make driving a juddery diesel feel more like a smooth petrol

looking at vans and wondering if i should discount anythng with a tow bar on the basis is has probably been used for towing.´, limiting the life of the clutch.

Least of your worries on things that are rated to carry 3te inside. Driving style would be more of a worry, though my transit was seriously pre loved when I got it at 150k and clutch was still going strong at 220k (no idea if it was done in the middle) but on a used vehicle it’s always a possibility. Something immaculate that had spent it’s life in 1st/2nd in town crawling through traffic would be more of a worry. Of course it’s hard to tell.

For most older diesels you can remove them and go back to a solid flywheel. Obviously slightly less refinement but in every one I’ve changed to solid I’ve never been able to tell!!!
Also the squeak on start up and switch off isn’t there.