Clutch and dual-mass flywheel wear on a used car

A worn clutch shows itself on a test drive: a bite point high up the pedal travel, revs that rise without the car speeding up, or a judder as you pull away. A failing dual-mass flywheel usually shows up as a rattle at idle or a shudder when you set off. The two parts work together and are often replaced together, so if one is worn, ask about the other. Ask the seller for the invoices, and if the car shows these signs, either price the repair into your offer or see the car and ask a mechanic.

What the clutch and flywheel do

On a manual car, the flywheel is bolted to the back of the engine and turns with it. The clutch sits between the flywheel and the gearbox. When you press the pedal, the clutch disconnects the engine from the gearbox so you can change gear or stop. When you let it out, the clutch plate grips the flywheel again and drives the car.

The clutch plate has a friction lining, like a brake pad. It wears every time it slips during a pull-away or gear change. So a clutch is a wear part. How long it lasts depends heavily on how and where the car was driven. Lots of town driving, hill starts and towing all wear it faster.

What a dual-mass flywheel is

Many modern manual cars, especially diesels, use a dual-mass flywheel rather than a single solid one. It is made of two heavy discs joined by springs and dampers. The idea is to soak up the pulses from the engine so they do not reach the gearbox and the cabin. That makes the car smoother and quieter.

The springs and dampers wear over time. When they do, the two halves of the flywheel can move more than they should, and the car starts to rattle and shudder. Some automatic gearboxes with two clutches also use a dual-mass flywheel.

The handbook or a garage can tell you whether a specific car has one.

Signs of a worn clutch

You can check most of these on a normal test drive.

• A high bite point. The clutch takes up near the top of the pedal travel. As the lining wears, the point where it grips tends to move higher.
• Slipping. The revs rise but the car does not speed up to match. This is easiest to notice when you accelerate firmly in a higher gear at lowish revs, on a clear road and within the speed limit.
• Judder. The car shakes as you pull away, especially in first or reverse.
• A burning smell, especially after a hill start.
• A heavy or spongy pedal, or one that does not come back up smoothly.
• Noise when you press or release the pedal, which can point to the release bearing.

One sign alone is not proof. A judder can come from engine mounts, for example. But a clear slip or a very high bite point means the clutch is near the end of its life.

Signs of a worn dual-mass flywheel

• A rattle or knock at idle that may change or go quiet when you press the clutch pedal.
• Vibration or shudder when pulling away, felt through the pedal, the floor or the seat.
• A clunk when you start or switch off the engine.
• Vibration at low revs in a high gear.

A worn flywheel can be hard to tell apart from other noises. A mechanic with the right tools can check how much free movement the flywheel has, but that usually needs the car on a ramp or the gearbox removed. On a viewing, your job is to notice the symptom and ask about it.

Why the two are often replaced together

To reach either part, a garage usually has to remove the gearbox. That is where most of the labour goes. Once the gearbox is out, it can make sense to replace the clutch and the flywheel at the same time, rather than pay the labour twice.

Clutch kits are often sold with a new flywheel included for that reason. A garage may also inspect the flywheel during a clutch change and recommend replacing it if it is worn. When you read an invoice, look at what was fitted:

• a clutch kit (usually the plate, the cover and a release bearing);
• a flywheel, and whether it was dual-mass or a single-mass conversion;
• a new slave cylinder or release bearing, where fitted.

"New clutch" on its own tells you less than an itemised list.

We do not give repair prices here because they vary with the car, the parts and the garage. Get a written quote for the specific car before you negotiate.

The MOT does not check the clutch

GOV.UK says the MOT does not cover the condition of the engine, clutch or gearbox. A fresh MOT certificate says nothing about how much life the clutch has left. Our guide to what the MOT does not check explains the other gaps.

The MOT history is still useful. Each test records the mileage, so you can see how far the car has gone since a clutch invoice and how hard it has been used. Our guide to reading MOT history explains how.

A short test drive routine

Our test drive checklist covers the rest of the drive. For the clutch and flywheel, add these steps.

1. Start from cold. Ask the seller not to warm the car up before you arrive, then listen at idle with the clutch pedal up and down.
2. Check the bite point. On level ground, let the clutch out slowly in first gear and note where it starts to grip.
3. Pull away several times, including in reverse and on a slope if you can. Feel for judder.
4. Try a firm acceleration in a higher gear at lowish revs on a clear road. Watch whether the revs and the speed rise together.
5. Listen when you switch off. A clunk or rattle as the engine stops can point to the flywheel.

If anything feels wrong, say so calmly and ask about it. Then ask for the invoices. On a high-mileage car, a clutch with no invoice is worth pricing in, and our guide to negotiating a used car price shows how to raise it.

Buying from a dealer

If you buy from a trader, the Consumer Rights Act 2015 says the car must be of satisfactory quality, fit for purpose and as described. Whether goods are satisfactory takes account of the description, the price and other relevant circumstances, so for a used car its age and mileage matter. Normal wear on a used clutch is not automatically a fault. If a clutch fails very soon after purchase, though, you may have rights. Keep the advert and any paperwork.

Private sales give you far fewer rights, so the checks before you buy matter more.

Frequently asked questions

What are the symptoms of a failing dual-mass flywheel?

A rattle or knock at idle that changes when you press the clutch, vibration or shudder when pulling away, and a clunk when the engine starts or stops.

How do I know if the clutch is slipping?

The engine revs rise but the car does not speed up to match, most noticeably when you accelerate in a higher gear at lowish revs. A high bite point and a burning smell are other signs.

Should the flywheel be replaced with the clutch?

Often, because both are reached by removing the gearbox. A garage may replace them together or inspect the flywheel and advise. Check the invoice to see what was fitted.

Does the MOT check the clutch?

No. GOV.UK says the MOT does not cover the condition of the engine, clutch or gearbox.