Head Gasket

 Head Gasket Replacement.

Your engine's head gasket is a very simple but extremely important component - one that's essential to your engine's well-being.

A blown head gasket can lead to serious damage. In some cases, it can lead to total engine failure. For this reason, it's useful to have some knowledge about the part, the role it plays, and how to make sure it's in perfect condition.

Here, we'll explain exactly how your vehicle's head gasket works, what a gasket replacement involves, and how much you can expect a head gasket repair cost to be. We'll also go into detail about some warning signs to look for that might tell you your head gasket needs attention.

Don't panic if you read this guide and feel like your head gasket might need replacing - we'll explain how to make sure you get the best possible deal from repair shops near me.

How much does a head gasket replacement cost?

A head gasket replacement is a big and very involved job that often results in a bill of $1,250 or upwards.

There are a couple of reasons this price could go up. First, there are any other repairs needed as a result of the head gasket failing. We'll touch on these a little more later - but if a gasket has failed and it hasn't received immediate attention, it can have knock-on effects to other components.

You may also want to think about any additional work that mechanics could do while they have the engine dismantled. Additional work may not be essential - but it often makes sense to have other small jobs (such as replacing other gaskets) done at the same time, rather than booking your car in again and spending more money in the near future.

Don't panic if your head gasket needs attention. It's a big job - but we can make sure you get the best price for a head gasket replacement in your area.

What is a head gasket?

A first glance, a head gasket is just a flat rectangular piece of metal with a series of shapes punched out of it. In practice, it's actually a specialist seal that withstands tremendous heat and pressure.

In the past, head gaskets were often made of a composite material that included fibreglass, cork, and other heatproof materials. Today, they're usually multiple layers of steel, sometimes with 'elastomeric' beads - a rubber like material that helps to seal separate sections of the engine.

What does a head gasket do?

To understand the head gasket's role in your engine, it's useful to get a quick overview of how an engine works.

In simple terms, there are two main sections of your engine - the engine block and the cylinder head.

The largest part of the engine is the 'engine block' - the part that houses the cylinders in which the crucial combustion happens - producing power that drives your car.

The cylinder heads sit on top of the block - above the cylinders that the engine's pistons live in. Each of these heads has a series of different jobs. They get air and fuel into the cylinders to help with combustion; they hold the spark plugs that ignites the fuel/air mix, then they get rid of the exhaust gases that are produced in the combustion chamber. The head also contains passages for coolant and oil.

The tiny explosion that happens inside each combustion chamber only results in power it creates pressure to force the piston back downwards - and this is where the head gasket comes in. This gasket seals the cylinder head and the engine block together - creating a totally sealed environment in which combustion occurs.

What happens if you have a head gasket failure?

Now you've got an overview of how the engine works and the role the head gasket plays, you can start to see why it's such a vital component.

Losing pressure

If a gasket fails, it usually means that the seal between the cylinder head and the engine block has been compromised and pressure or a fluid is being lost.

A lack of pressure reduces the effectiveness of the combustion that happens within the engine. So, a lack of pressure will result in a lack of power. This could make your car feel like it's got less power than usual when you push the accelerator. Since each cylinder is independently sealed, you may just get a lack of pressure in one cylinder - making your car appear to stutter or acceleration appear jumpy and sporadic.

Contamination

In some cases, a failed head gasket will result in cross contamination of fluids within your engine. Remember we said the gasket has a series of different cutouts? Well, those different cutouts do different jobs - some sealing areas where engine oil flows, other sealing the cylinders, and others sealing parts of the cooling system. If the head gasket fails in a way that means oil or coolant can get into parts of the engine it shouldn't, you can end up with serious engine damage - with problems in both the head and the block.

What are some head gasket leak warning signs?

Since the head gasket seals different components and sections of the engine, the symptoms of a leaking gasket will depend where and how it is damaged.

Here are some warning signs to look out for that could indicate damage to the head gasket:

Low power or jerky acceleration

Not getting the expected power when you press the accelerator? The gasket could be compromised and making your engine lose pressure.

White smoke from the exhaust system tailpipe

White smoke coming from the exhaust tailpipe could indicate the the gasket is letting coolant get into the cylinder - polluting the combustion process and producing white smoke.

Is your engine overheating?

If your engine temperature is higher than usual, it might indicate low coolant levels - sometimes caused by coolant escaping and being burned in the combustion process.

Spotted any leaks?

Signs of leaks - either oil or coolant - coming from the join between the cylinder head and block could be a sign that the gasket is damaged and letting fluids out.

Losing coolant with no coolant leaks

Low coolant level with no signs of a leak? Your coolant could be getting burned off due to a leak in the gasket.

Engine oil looking milky

Engine oil circulates, and if it becomes contaminated as it works through any of the engine components, it could turn a strange colour. Milky oil might suggests it's got coolant in it.

Bubbling in the radiator or cooling system

If you're seeing bubbles anywhere in the coolant, there could be a pocket of air in the system. This could be caused by air pressure in the cylinder head being forced into the system.

What do head gasket repairs involve?

Since the actual head gasket itself comes in a set that usually costs a couple of hundred dollars, you can probably see virtually the entire cost of a gasket replacement is accounted for by work carried out by a repair shop or mobile mechanic.

Depending on the make and model of car you have, replacing a head gasket may involve lifting the engine out of the engine bay. Even if it doesn't, there's a huge amount of work involved with accessing the cylinder head and removing it from the engine block.

The head gasket replacement process

• An assessment, confirming that the head gasket has failed
• Oil and coolant being removed from the engine
• The cylinder head will be removed from the engine. Sometimes the condition will be assessed on-site, but it may need to be sent to a specialist for reconditioning
• The damaged gasket will be replaced and the block will be checked for any damage
• With any damage repaired, the new head gasket will be fitted - then the cylinder head and all other component will be put back into place
• The engine and coolant system will be refilled
• The vehicle will be pressure tested and road tested to ensure normal performance

Can you repair a head gasket instead of replacing it?

In theory, it's possible to make a crude repair to a head gasket rather than going to a workshop for a head gasket replacement. There are sealant products on the market that promise permanent results and online videos that rate sealant products highly.

The trouble is, even if the sealant is effective, it doesn't put right any damage that's been done to the engine while the head gasket was leaking. At the very least, you'll need to buy and use the sealant - as well as replacing all the oil and coolant in your vehicle to get rid of impurities.

If you go down this route and it turns out that there's further damage done to the cylinder head, you'll be hundreds of dollars down and still requiring professional mechanics services.

Is a repair a good idea?

Our verdict? Even if you think you might be able to use a sealant product to repair your gasket - check with a mechanic first. Years of experience dealing with blown gaskets will mean they have a good idea about whether you need further work doing.

Don't worry about being told you need work when you don't. If you get quotes for a head gasket replacement from Auto Hero, you'll get quotes from workshops that promise no pressure and no additional unnecessary work - just a professional opinion you can trust.

Need a head gasket replacement local to you?

If you suspect there's something wrong with your head gasket, we recommend that you do not continue using your vehicle. Continued use when you have a head gasket problem could lead to very serious mechanical problems.

Stop - and get a quote from Auto Hero. We'll save you hours of effort and put you in touch with the best workshops near you. We're the most reviewed mechanical work comparison site in Australia - so you'll be able to choose a mechanic, safe in the knowledge that they've received real reviews from customers in your area.