How To Tell A Bad Clutch

[miss_mondeo]

18 hours ago, miss_mondeo said:

Just jumping in on this thread as I have similar symptoms and have googled it to death - two issues which I've always thought were related but reading this possibly not...

I have a 2014 2.0 diesel mondeo, 130,000 on the clock. I've noticed these symptoms for a long time but no garage has got to the bottom of it, no warning lights or codes but so annoying to drive. It doesn't happen all the time, seems to come and go during a journey but happens at least every time I drive.

So, upon hard acceleration after changing gear (like pulling away at lights) through all the gear changes there is a real lag in acceleration - a good 1/2 to 1 second of nothing, then it picks up speed. I haven't particularly noticed revs going crazy but I'll pay more attention to that. It continues to cruise quite happily once up to speed. Like I say, this isn't all the time, but at some point into a journey it will start doing it, then maybe later in the same journey it will stop.

What I've noticed though and I have thought they were linked, is that when it seems to be experiencing the lag problem, the fan is also on and there is a low, quick thumping sound coming from behind the dash. It's noticeable when you pull up stationary at lights say, hear the fan/thumping, then I know it's going to play up when pulling away.

I'm going to try the clutch test others have recommended on here, but is there any way these symptoms could be linked or is it just coincidence? Or does anyone have any other ideas? Other than that it's a lovely car to drive and I really don't want to have to change it! I'd happily (ish) pay to have the clutch done if that cured it, it's just infuriating not being able to diagnose.

Thanks in advance for anyone reading this!

Update, did the clutch test thing and it stalled perfectly. Also checked the revs after changing gear and accelerating - rather than going up they're actually sticking for a second and then picking up. So looks like it's back to the drawing board.... Actually disappointed it's not the clutch as mad as that may sound!

[Tdci-Peter]

13 hours ago, miss_mondeo said:

when it seems to be experiencing the lag problem, the fan is also on and there is a low, quick thumping sound coming from behind the dash.

It certainly did not sound like either of the clutch slip problems I have experienced, once a clutch loses grip it usually needs the throttle to be almost fully released to allow it to grip again.

Lag in acceleration sounds like an engine control or sensor problem. I think you need to try to pin down those odd noises, as they seem the only diagnostic clue at the moment. I assume fan means the radiator cooling fan, though I can not hear mine while I am inside the car, on or not. Other than a hot engine, two other times a radiator cooling fan is on is with the air-con on, or while doing a DPF regen. Thumping sounds are a bit unusual, a DMF can do it at idle (mine sometimes does), but it is quite slow. Relays in the passenger fuse box can click. Engine big ends, pistons etc can tap or thump if worn, loose wiring, connectors or other mechanical parts can tap against something else if not secured properly. So being able to hear it stationary with the bonnet up might be a big step forward.

[Ant22]

Hi I’ve just brought a 55 plate mk  2 1.6 zetec the clutch pedal is right at the top with in 1/2 inch it’s the first time I’ve ever experienced this I’ve spoken to the old owner and he’s telling me it’s fine on focus there known for this am I losing the plot or is he correct I’ve read a few comments and seen to go try the gears on level ground but thought I’d still ask the question thanks guys 

[Tdci-Peter]

On 6/24/2022 at 8:02 PM, Ant22 said:

I’ve just brought a 55 plate mk  2 1.6 zetec the clutch pedal is right at the top with in 1/2 inch

It is not the height of the bite point that matters, it is the pedal force and hence hydraulic pressure that matters. These Fords are noted for often having high bite points. Starting from a fully engaged clutch with no pedal force, as you start to apply force to the pedal this takes away some of the clamping force on the clutch plate. Once you take away sufficient clamping force, then the clutch will start to slip, regardless of the amount of pedal movement.

The best test is still to apply the throttle while going up a hill. Maximum torque on a standard 100HP 1.6 is at around 4000RPM, though it is fairly flat from 3500RPM up. So stay in a gear that allows the engine to run at about 3500RPM up a long straight hill, and floor the throttle. You will clearly hear if the clutch slips, with RPM rising much faster than the speed. Also releasing the throttle will reduce RPM with no speed decrease, and there may be a just noticeable jolt as the clutch stops slipping.

Slip can also happen after a gear change where you apply torque while releasing the clutch, ie a racing type change. Briefly releasing the throttle will allow the clutch to fully engage, then in the early stages of slip it will stay engaged even at high throttle openings. The sound, feel and RPM reading all combine to make this quite obvious if you test it where you can concentrate on the car, ie in light traffic conditions.

If you can't make the clutch slip at max torque like this, then it is not worn out. There plenty of other possible clutch problems, like juddering on take-up, odd noises while the pedal is held down, drag causing difficulty changing gears. But on the slipping clutches I have had, I noticed this problem very quickly from the obvious RPM rise. Once slip starts, it rapidly develops.