How much does a head gasket repair cost?
Replacing a head gasket in the UK typically costs between £450 and £2,000, and the RAC puts the average at around £721. The gasket itself is one of the cheapest parts on the car, often £50 to £150, so you are really paying for labour. Stripping and rebuilding the top of an engine takes most garages somewhere between six and sixteen hours, and the cylinder head usually has to be skimmed and pressure tested as well. Small four cylinder cars sit at the bottom of the range and larger or premium engines at the top.
Very few repairs make a driver wince like this one. The part costs less than a decent set of wiper blades, and the bill can be four figures. That gap is the whole story of a head gasket job, and understanding it is what stops you either overpaying or writing off a car that did not need writing off. This guide sets out what the work actually costs in the UK, what makes one quote so different from the next, and how to judge whether the repair is worth doing at all.
How much does a head gasket repair cost?
A full head gasket replacement in the UK typically costs between £450 and £2,000. The RAC publishes an average of around £721, which is a fair middle marker for an ordinary family car. Most drivers with a mainstream hatchback or saloon end up somewhere between £800 and £1,200 once the machine shop work is included.
These are market ranges rather than an official price. Unlike the MOT, where the fee is capped by law, engine repair is priced by the garage according to its hourly rate and how long the job takes on your particular engine. The figures below are indicative, and the only number that matters is a written quote for your car.
| Type of car | Typical total cost | Why |
|---|---|---|
| Small hatchback, small 4 cylinder | £450 to £900 | Cylinder head is accessible, fewer ancillaries to remove |
| Family car, larger 4 cylinder | £800 to £1,200 | More to strip, often a timing chain rather than a belt |
| SUV or four wheel drive | £1,200 to £1,800 | Heavier components, tighter engine bay, longer labour |
| Premium or 6 cylinder engine | £1,400 to £2,000+ | Two cylinder heads on a V engine means two of everything |
What you are actually paying for
The head gasket itself is usually £50 to £150 as part of a gasket set. Everything else on the invoice is access and reassembly. To reach the gasket the mechanic has to take the top of the engine apart: the cambelt or timing chain, the inlet and exhaust manifolds, the coolant hoses, the injectors or spark plugs, the rocker cover and frequently the turbo. The cylinder head then comes off, goes to a machine shop to be pressure tested and skimmed flat, and comes back to be rebuilt with new head bolts to a specified torque sequence.
Here is a worked example of a £900 invoice on a mid sized four cylinder family car, which is close to the national average:
| Line on the invoice | Typical amount |
|---|---|
| Labour, 8 hours at £70 an hour | £560 |
| Head gasket set | £110 |
| New head bolts, coolant, oil and filter | £120 |
| Cylinder head skim and pressure test | £110 |
| Total | £900 |
Labour is roughly two thirds of it. That is why a garage charging £60 an hour and a franchised dealer charging £140 an hour can quote hundreds apart for identical work, and why main dealer against independent garage matters more on this job than on almost any other.
What makes one quote higher than another
- Labour hours. Published times for this job range from about six hours on a simple engine to sixteen or more on a complicated one. Ask how many hours the quote is based on.
- The hourly rate. UK garages commonly charge between £60 and £100 an hour, with dealers higher and city centre sites higher again.
- Whether the head survives. A skim and pressure test is routine. A cracked or badly warped head is not, and a replacement or reconditioned head can add several hundred pounds.
- What else comes off anyway. If the cambelt has to be removed to reach the head, it is usually false economy not to replace it while it is out. Our guide on when to change a cambelt covers the intervals.
- Collateral damage. If the car was driven hot, the water pump, radiator, thermostat or even the bearings may need attention too. A radiator replacement is a common add on.
How do I know the head gasket has gone?
A head gasket seals the join between the engine block and the cylinder head, keeping combustion pressure, coolant and oil in three separate places. When it fails, those three start to mix, and the symptoms follow from which passage has broken through.
| What you notice | What it usually means | Sensible next step |
|---|---|---|
| Thick white smoke from the exhaust that smells sweet | Coolant burning in a cylinder | Stop driving, arrange recovery |
| Creamy beige sludge under the oil filler cap | Coolant mixing with the oil | Do not run the engine, book a garage |
| Coolant level dropping with no visible leak | Coolant going somewhere internal | Pressure test and combustion gas test |
| Bubbles in the expansion tank when running | Combustion gases in the coolant | Strong indicator, get it confirmed |
| Overheating that comes back after a top up | Loss of coolant or a circulation fault | See why a car overheats |
| Misfire or a sudden loss of power | Compression leaking between cylinders | Diagnostic check before spending |
Several of these overlap with cheaper faults, which is exactly why a diagnosis comes before a quote. A sweet smell alone might be a leaking heater matrix, and white vapour on a cold morning is usually just condensation. Our guides to what a burning smell means and why a car loses power cover the alternatives, and what a diagnostic check involves explains how a garage narrows it down. A combustion gas test on the coolant takes minutes and is the usual way this is confirmed.
Will a blown head gasket fail an MOT?
It can fail on two separate grounds. Under section 8 of the DVSA MOT inspection manual, an exhaust that emits dense blue or clearly visible black smoke for a continuous period of five seconds at idle is a Major defect, as is excessive smoke during acceleration that would obscure the view of other road users. A Major defect is a fail.
The same section covers leaks. Fluid leaking excessively and likely to harm the environment or pose a safety risk is a Major defect, and fluid leaking continuously in a way that poses a serious risk to road safety is a Dangerous one. For engine oil and coolant the threshold is a pool larger than 75mm across forming within five minutes. So a gasket failure that pushes coolant out under pressure is an MOT problem as well as an engine problem. If you want to see what a car has previously been pulled up on, you can check its MOT history, and our MOT checker points you at the free GOV.UK service for the due date.
Is the repair worth doing?
This is the real decision, and it is arithmetic rather than sentiment. Put three numbers side by side: the written quote, what the car would sell for in working order, and what else is due in the next twelve months.
- Repair usually makes sense when the quote is comfortably under half the car's value, the service history is good, the MOT has months left and the rest of the car is sound.
- Repair is marginal when the quote is around half the value. Here it often turns on whether the cambelt, clutch and tyres are recent, because replacing the car means paying for those again anyway.
- Repair rarely makes sense when the quote approaches or exceeds the value, the car has been driven hot for a long time, or the head has been found to be cracked.
If you do decide to let the car go, the rules are worth knowing. GOV.UK requires a scrapped vehicle to go to an authorised treatment facility, and you must tell DVLA once you have done it or you risk a fine of £1,000. You hand the V5C to the facility but keep the yellow section for selling or transferring to the motor trade.
Can you prevent it?
Mostly, yes, because the great majority of head gasket failures start as a cooling problem that was driven on. The gasket rarely fails on its own on a well maintained engine. Keeping the cooling system healthy is the prevention, and it is cheap by comparison.
- Check the coolant level when the engine is cold, and treat a level that keeps dropping as a fault rather than a chore.
- Have the coolant changed at the interval in your handbook. Old coolant loses its corrosion inhibitors and lets the system silt up.
- Never ignore the temperature gauge or a coolant warning light. Pull over, let it cool, and get it looked at.
- Keep an eye on the oil. Knowing how to check your engine oil takes two minutes and catches contamination early.
- Service the car on schedule. Most cooling faults are spotted on a ramp long before they become expensive.
The Highway Code asks drivers to check fluid levels at least weekly, which on this particular fault is the single most useful habit you can have.
How to keep the bill down
- Get the fault confirmed first. Pay for a proper diagnosis, including a combustion gas test, before authorising a strip down. It is a fraction of the repair cost.
- Get two or three written quotes. The spread on this job is unusually wide, and a quote that itemises hours, parts and machine shop work is easy to compare.
- Ask what happens if the head is cracked. Agree in advance whether the garage calls you before ordering a replacement head.
- Bundle the work that is already exposed. Cambelt, water pump, thermostat and hoses cost far less fitted while the engine is apart.
- Compare independents as well as dealers. On a job that is two thirds labour, the hourly rate is the biggest single lever you have. How to choose a good garage covers what to look for beyond price.
The bottom line
Budget £450 to £900 for a small car, £800 to £1,200 for an ordinary family car and £1,200 to £2,000 or more for something larger or premium. Assume roughly two thirds of that is labour, expect the cylinder head to be skimmed and pressure tested, and insist on an itemised written quote before anything comes apart. Above all, do not drive a car that is overheating or blowing white smoke, because the difference between a gasket and an engine is usually a few miles.
Because so much of this bill is the hourly rate, comparing local garages is worth real money on this repair rather than a few pounds. You can compare garages near you, see their ratings and opening hours and send a request in about a minute. You pay the garage directly, and there is no booking fee. If the car is also due its annual test, our guide to what an MOT should cost is a useful companion.
Key takeaways
- Typical UK cost is £450 to £2,000 for a full head gasket replacement. The RAC publishes an average of around £721.
- The gasket costs £50 to £150. Labour is the bill, usually six to sixteen hours depending on how buried the cylinder head is.
- Expect the head to be skimmed and pressure tested at a machine shop. If it is cracked or badly warped you are into a replacement head, which changes the sum completely.
- Visible dense blue or black exhaust smoke is a Major MOT defect under section 8 of the DVSA inspection manual, so a blown gasket can fail the test as well as damage the engine.
- On an older car the repair can cost more than the car is worth. Get two or three written quotes before you decide, because the spread on this job is unusually wide.
Frequently asked questions
How much does it cost to replace a head gasket in the UK?
Most UK drivers pay between £450 and £2,000, and the RAC publishes an average of around £721. Where you land depends far more on the engine than on the gasket. A small four cylinder hatchback with the cylinder head sitting on top of the engine and plenty of room around it is a much shorter job than a transversely mounted V6 buried under an inlet manifold. Ask for the quote to be split into parts, machine shop work and labour hours so you can see what is driving the number.
Why is a head gasket so expensive when the part is cheap?
Because you are paying for access, not for the gasket. The gasket sits between the engine block and the cylinder head, which means the mechanic has to remove the cambelt or timing chain, the inlet and exhaust manifolds, the cooling system connections and often a good deal more before the head can come off. Reassembly has to be done to the manufacturer torque sequence with new head bolts. Six to sixteen hours of labour at typical UK rates of £60 to £100 an hour accounts for most of the bill.
Can you drive with a blown head gasket?
You should not. A failed head gasket lets coolant, oil and combustion gases mix, and driving on usually turns a gasket job into a cylinder head or an engine. Overheating warps aluminium, and coolant in the oil destroys bearings. If you see white smoke from the exhaust, a creamy deposit under the oil cap, or the temperature gauge climbing, stop somewhere safe and have the car recovered rather than driven. The few miles home are usually what turns a gasket bill into an engine bill.
Will a blown head gasket fail an MOT?
It can, in two separate ways. Section 8 of the DVSA MOT inspection manual records a Major defect where the exhaust emits dense blue or clearly visible black smoke for a continuous period of five seconds at idle, or excessive smoke during acceleration that would obscure the view of other road users. Separately, fluid leaking excessively is a Major defect and fluid leaking continuously in a way that poses a serious risk to road safety is a Dangerous one. Engine oil and coolant leaks count when they form a pool larger than 75mm across within five minutes.
Do head gasket sealants work?
Sometimes, briefly, and rarely in a way that solves the problem. A chemical sealant can slow a very small leak between a coolant passage and the outside world, which is why some drivers use one to get a car through a short journey. It will not repair a gasket that has failed between cylinders or into the oil, and it can clog a radiator or a heater matrix while it is in there. Treat it as a way of moving a car to a garage, not as a repair, and tell the garage you have used one.
Is it worth repairing a head gasket on an old car?
Compare the written quote against what the car is honestly worth and what else is due. If a £900 repair is going onto a car worth £1,200 that also needs two tyres and has an MOT in a month, the sums rarely work. If the same repair goes onto a well maintained car with a fresh cambelt and two years of use left in it, it often does. If you decide to scrap it, the car must go to an authorised treatment facility and you must tell DVLA afterwards, or you risk a £1,000 fine.