DMF or solid replacement?

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  • DMF or solid replacement?
  • Premier Icon aracer
    Subscriber

    Dual Mass Flywheel has gone on my 08 Mondeo. It seems I can either replace with another DMF or go for a solid replacement (which is a little cheaper). Googling suggests I could get more vibration with a solid and it might result in engine wear – though bloke at the garage suggests the latter is scaremongering.

    Any thoughts?

    DM52
    Member

    How many miles did it take for the dual mass flywheel to expire?

    Are you intending to do that many again?

    Premier Icon aracer
    Subscriber

    Almost 130k and no I don’t think I’ll do that again – but then I’ve only owned it for the last 8k, so might be harder on it than the previous owner (who was doing 30k a year, presumably mainly long motorway trips). That is kind of how I’m thinking though.

    Inbred456
    Member

    DMF’s are supposed to protect the gearbox from engine vibration as well as taking some of the vibration out of the cabin as well. Just go for a normal DMF it will almost certainly last longer than the pump and injectors anyway.

    Premier Icon mattbee
    Subscriber

    You know that nice smooth pick up you got when pulling away in 1st or 2 nds before the dmf went? You’ll kiss goodbye to that fitting a solid flywheel.
    Just replace with another dmf, not worth the loss of performance to save a few quid.

    Premier Icon footflaps
    Subscriber

    You know that nice smooth pick up you got when pulling away in 1st or 2 nds before the dmf went? You’ll kiss goodbye to that fitting a solid flywheel.

    Can’t say I ever noticed a non smooth pick up on a car without a DMF…..

    Premier Icon mattbee
    Subscriber

    But was it a car with a drivetrain designed around the use of a dmf?
    There are people over on the T5 forum who have tried using a smf instead of dmf and ended up replacing it again with a new dmf due to the adverse affect on drive ability.
    Typical STW though. Nothing useful to add to the thread, but I’ll jump on the chance to pick a hole in someone else’s reply…

    Premier Icon cloudnine
    Subscriber

    Its lasted 130k miles.. Put another DMF in and just make sure you buy a decent brand and clutch

    falkirk-mark
    Member

    I have wondered if the timing belts should be changed more regularly if you do away with your DMF my car is summit like 120,000 miles whereas earlier non DMF cars were half that.

    Premier Icon takisawa2
    Subscriber

    SMF on a Transit van yes, lots do, but not a nice Mondeo with bags of torque.
    I wouldn’t. Drive take up could end up a bit fierce… 😐

    Premier Icon Northwind
    Subscriber

    I did a wee comparo, I’ve got a 2.2 tdci mondeo with dmf (original, at 120000 miles, so I had a reason for researching replacements 😉 ) and had a wee spin in a 2.0, so fairly comparable in parts but about 50% less powers. Anyway, it wasn’t so terribly different- yes a wee bit less nice off idle and at low revs, the owner said he compensates with just a wee bit more of each foot, more revs and more careful clutch takeup. Thinking back to driving standard 2.0s, to be honest it’s too long ago to be totally sure but I reckon the difference between the two is much the same- ie it’s not just my car’s bigger engine making it nicer to drive on/off.

    I could live with it no bother but the DMF is noticably nicer and, well, to me it just feels like it loses one of the things that makes a chunky diesel so nice to drive. So no chance at all that I’m fitting a solid in mine when the current one inevitably dies. YMMV of course, I love how diesels drive , not everyone is so easily aroused :mrgreen:

    Premier Icon PePPeR
    Subscriber

    I wouldn’t change to a normal flywheel either, 130,000 miles again would be just fine.

    I’ve used DMF’s for the last 10 years and only had one go wrong in over 400,000 miles (ford at only 30,000 miles)

    Premier Icon aracer
    Subscriber

    mattbee wrote:

    Typical STW though. Nothing useful to add to the thread, but I’ll jump on the chance to pick a hole in someone else’s reply…

    On the contrary you gave real anecdotal evidence of there being a noticeable difference in a T5.

    Thanks all – I think that’s unanimous isn’t is, and also in agreement with my own thinking. Interestingly 2 out of the 4 garages I tried wanted to sell me a solid though. It is kind of scary spending >£1k on a car I only paid £4k for, but then when I bought it I always had a budget of £2k for major repairs in my head (at which point it will have had the major parts replaced which one bought s/h for £6k wouldn’t).

    Though no thanks to f-m for reminding me the rest of that budget’s going on replacing the timing belt 🙁

    Premier Icon Northwind
    Subscriber

    It might be worth your time to to the whole shebang while the engine’s out- clutch and slave cylinder as well. Ford often use a concentric slave cylinder so if it pops the engine’s got to come back out to replace a very cheap component, annoying

    Premier Icon molgrips
    Subscriber

    And drive to preserve the next one. Keep revs above 1300 and above 1600 if you are going to floor it.

    It is kind of scary spending >£1k on a car I only paid £4k

    Don’t get hung up on it. The MARKET value and the real value of a car aren’t the same. You’ll now own an old Mondeo with a brand new flywheel. If a DMF benefitted the car when it was new, it’ll still benefit it at 160k miles, cos it’s still the same car.

    If you were to sell it and get another, the DMF on the new car could fail tomorrow. This way you can be pretty confident you won’t have to worry about it.

    It’s worth looking after old cars imo. I could have replaced my Passat with a brand new one, but I’d be £20k down and still have a very similar car. Now please make some unfunny ECU gags.

    Premier Icon aracer
    Subscriber

    Thanks for the reassurance, molgrips, but I’m sure you’ll understand not taking your advice on maintaining old cars! As I said, the budget was in my head when I bought the car – was hoping I might get lucky, but a 5yo Mondeo for £5.5k with new tyres, clutch and DMF still looks very good value.

    Northwind – all quotes I’ve got include replacing clutch and release bearing – nobody seems to suggest not doing so. I’m assuming a new clutch comes with the slave cylinder?

    mrmonkfinger
    Member

    I’m assuming a new clutch comes with the slave cylinder?

    not always

    but, cheap part, with expensive labour if it ever goes, might as well get it done while they’ve dropped the box

    Premier Icon molgrips
    Subscriber

    Thanks for the reassurance, molgrips, but I’m sure you’ll understand not taking your advice on maintaining old cars!

    You should. I’ve learned far more than most people know about cars through the ECU thing. Which wasn’t caused by my lack of knowledge incidentally, it was caused by the mechanic’s lack of knowledge 🙂

    maxtorque
    Member

    Basically, considering the cost, complexity and potential lack of reliability of a DMF, the manufacturers would avoid fitting one if theu thought they could get away with it. But they fit them, and so should you!

    Yes, the car will be smoother and driver nicer with one in place, but what you can’t feel is the massive torsional loads that the DMF is suppressing, as they are effectively contained by the rotating inertia of the engine and the mass of the car. With a SMF, these forces will slowly but surely start to have an effect. That effect can varry from a little as slightly raised gearbox dog wear, to a critical failure of a cam belt, a crankshaft, a gear cluster and propshafts/driveshafts.

    So, yes, if you replace the DMF with a SMF, then yes, you will save a little money in the short term, but could set yourself up for a big future fall…….

    Premier Icon aracer
    Subscriber

    Paul wrote:

    So, yes, if you replace the DMF with a SMF, then yes, you will save a little money in the short term, but could set yourself up for a big future fall…….

    It wasn’t so much saving a little money now – that’s trivial all things considered – as not having to replace the DMF again in the future. But everybody appears to agree with my own initial thoughts. I asked one place to quote for a DMF when they came back with a quote for a SMF as that’s what I wanted – though it’s nice to get confirmation from everybody else.

    maxtorque
    Member

    Well, as mentioned, DMFs are really service items. Long life service items but they wear as you drive the car. Also as previously mentioned, avoiding driving in the zones where the DMF gets a pasting (< say 1400rpm @ ? 50% throttle) will help extend it’s life.

    I would expect most people to get over 100k miles from one assuming they had a modicum of mechanical sympathy!

    Premier Icon aracer
    Subscriber

    If I get 100k I’ll be happy – though thanks for the driving tips. I do tend to drive at quite low revs, so will try and avoid that a bit more.

    maxtorque
    Member

    There is no issue with driving at low revs, just avoid large throttle openings at low revs!

    Premier Icon Northwind
    Subscriber

    aracer – Member

    Northwind – all quotes I’ve got include replacing clutch and release bearing – nobody seems to suggest not doing so. I’m assuming a new clutch comes with the slave cylinder?

    I have to say, I don’t know 100% if your model has a concentric cylinder- it’s perfectly possible for a car to have a pretty easy to replace slave, in which case, it’s maybe not worth bothering.

    But, well, if your garage is suggesting to you to change the friction plates and bearings- which is good- they damn well should be suggesting you replace the slave, if it’s a tricky one to replace- all the same arguments apply. So worth checking with them, but if they’re good, then they’ve probably just shorthanded that all to “clutch”.

    Premier Icon aracer
    Subscriber

    Well most places are quoting a “clutch pack” – I think it was only the main dealer which separated clutch and release bearing on the quote (and incidentally their quote was only £50 more than the cheapest). The place I think I’m going to I checked that clutch pack meant plates and release bearing, so I’ll also check on the slave cylinder when I go in.

    Can I just add that this thread is an example of what’s great about STW – every single post adding something.

    nwilko
    Member

    avoid driving with engine under high load at low road speed, such as 4th gear 1300rpm in town, the DMF has to absorb lots of oscillation which wears it out.
    keep the engine speed up and load down for long DMF life.

    Premier Icon benji
    Subscriber

    If it’s the one I’m thinking of it’s a concentric slave, so the release bearing is part of the slave cylinder.

    Premier Icon porter_jamie
    Subscriber

    I happen to be a clutch actuation engineer for a large oem with blue ovals. The release bearing is part of the slave cylinder. You absolutely should change this whilst the gearbox is off. We call it a csc, concentric slave cylinder. Make sure they bleed it properly afterwards. Only use dot4. Don’t let them gob tons of grease all over the input shaft because it will go in the clutch and dmf and make them fail early. Re dmf or not i probably would but make sure its a pukka one not some pattern shit. Luk = good. The slave is made by FTE.

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