How Much Does A Head Gasket Replacement Cost in the UK?

A head gasket is a seal between the engine block and cylinder head. The head gasket seals the cylinders to prevent coolant and oil from leaking into the cylinders. A “blown” head gasket can cause oil and coolant to mix, leading to engine damage. Head gasket replacement is a major repair that should be done by a professional mechanic.

How much does it cost to replace a head gasket?

The average cost of replacing a blown head gasket is £750, with prices ranging from £500 to £1000. On some cars, this cost can even go over £1200 due to the amount of time needed to carry out the entire replacement. Hence, the exact price of a head gasket replacement depends largely on your car and the parts your car's manufacturer recommends.

There are several reasons why a head gasket can fail; however, the most common cause is overheating and extreme pressure. Sudden loss of coolant can also cause overheating and a “blown” head gasket.

Your location can also be a key factor in determining the price of a head gasket repair. For example, average hourly labour rates and demand in cities like London is around £50-£100 while in towns with lower demand, the labour rates can range from £35-£50. The type of mechanic, for example, a mobile mechanic vs a dealership garage technician can also affect the total cost of a head gasket repair.

To avoid having car owners overpaying and get a fair price for a head gasket replacement, we use real time data of thousands of car makes and model data, local labour prices for head gasket repairs and replacements and head gasket part prices to provide an instant fair quote. Simply enter your vehicle registration number and postcode to get an instant price for a head gasket replacement for your car.

Average cost of a head gasket replacement by manufacturer

Signs your head gasket needs a replacement

• Engine overheating
• Engine misfiring
• Loss of coolant
• White smoke from exhaust
• Low power or performance issues
• Oil in the coolant tank
• Milky-coloured oil
• Bubbles in radiator
• Slow engine start

White smoke coming from exhaust

A leak in the combustion chamber allows coolant into the combustion chamber, which is burned off to produce this white smoke. Sometimes it may even result in a sweet smell coming from the exhaust both of which are common signs of a blown head gasket.

Loss of coolant

A head gasket that has blown will cause your coolant level to drop due to the leak. Low coolant will result in an overheating engine which is quite noticeable to the driver. The cooling system can also become over pressurised resulting in overheating, cabin heater problems and coolant loss through the system pressure cap

Milky-coloured oil

A tell-tale sign of a blown head gasket is white-coloured milky-looking oil.
To check the colour of the oil; remove the oil cap or engine oil level dipstick under the bonnet and take a look - if the coolant has leaked due to the leaking head gasket then this will be evident with the milky nature of the oil.

Some other signs that could point out to a faulty head gasket include:

-Low power or performance issues
-Oil in the coolant tank
-Bubbles in radiator
-Slow engine start

Frequently asked questions about head gasket replacement cost

What does a head gasket replacement involve?

Engines differ in their processes and components, but most engines will require the following basic tasks to be done for a head gasket replacement:

• Mechanics will check that the head gasket is faulty by conducting tests such as a combustion gas test or compression test depending on the situation.
• Once properly diagnosed, the engine will be drained of oil and coolant.
• Components will be removed to allow access to the rocker cover and ultimately, the cylinder head bolts.
• The engine timing will be locked in place using specifically designed pins and locking tools.
• The timing belt will be removed, or the timing chain loosened off and moved off the camshaft sprockets.
• The cylinder head will then be undone in a specific sequence.
• Following the removal of all bolts, the cylinder head will be removed and the engine block and cylinder head will be cleaned of old gasket residue. In the case of the majority of cylinder heads, it will need to be pressure tested to ensure its structure is sound and then go through a process called skimming. This process ensures that the surface the new gasket will come into contact with is perfectly flat and clean.
• Once the mechanic has completed the work on the components, the engine is reassembled with a new cylinder head gasket. In the case of a timing belt-driven camshaft(s), this belt will be renewed along with a new water pump if it is on the timing belt circuit.
• Once the engine is back together due to the blown head gasket, the cooling system will be refilled and the oil replenished along with a new filter.
• If the oil has become contaminated with the coolant, an additional oil flush may be required and likewise, if the cooling system has become contaminated, the cooling system will be flushed.
• Once everything is assembled carefully back together, the mechanic will run the engine.
• In the end, a road test will confirm that everything is working properly as soon as the engine reaches normal operating temperature. Any error codes that may be present will also be cleared and re-evaluated.

Of course, this is not a fully exhaustive list of what will be done as each engine has its own requirements and also differs in its parts.

Does a head gasket sealer work?

A head gasket sealer is a solution that is used to seal the head gasket of an engine. It works by creating a chemical reaction that causes the sealer to harden and create a temporary seal. It’s important to remember that sealers are only a temporary fix and in some cases can cause further damage if not done properly.

Using a head gasket sealer is a cheaper fix but keep in mind that may not be a cost-effective solution in the long term.

Why are head gasket repair and replacements so expensive?

A head gasket replacement is expensive because it is a difficult and time-consuming repair and in some cases takes 10 hours. The head gasket is responsible for sealing the engine block and cylinder head, and it is located between the two which can be difficult to access and time-consuming to put back together. The head gasket part itself can be inexpensive but the cost is high due to the labour charges and time required to do the actual job.

How long does a head gasket repair take?

Head gasket replacement is one of the most complex jobs for a mechanic and can range from 5 hours to more than a day. Ultimately, the time that the job will take will depend on a number of factors, like your vehicle's make and model, year, type of engine, as well as other factors. Select your car at the top of this page for information on job time and cost for your vehicle through ClickMechanic.

Can I carry out a head gasket repair myself?

Replacement of head gasket requires a high level of auto repair expertise and in-depth knowledge of engine systems. It may require removing the engine along with associated components to access and reinstall the head gasket.

Unless you are a qualified mechanic with the required skills, training and equipment to do the job, we strongly recommend a head gasket replacement is only carried out by a professional mechanic. ClickMechanic can help get you a vetted and local mechanic to carry out the work. Just enter your postcode and your car's registration number at the top of this page and select the work needed to get an instant fixed price upfront.

What else could be the problem if my head gasket isn’t broken?

If you’re experiencing overheating and other symptoms and have ruled out the head gasket then it could be one or more of the following:

• Cooling system - overheating is often a sign of a problem within the cooling system such as a failing water pump
• Oil leaks - leaks from the valve cover or oil pan can lead to oil contamination
• Exhaust system - a cracked exhaust manifold or damaged catalytic converter, for example, can cause noise, vibrations, and poor engine performance
• Ignition or fuel system - if you are experiencing issues with starting the car or overall engine performance, it’s likely something to do with the ignition or fuel components such as spark plugs or fuel filters. A closer inspection by a mechanic will help narrow down the exact cause.