Signs that Your Head Gasket is Failing

head gasket on an engine

Your head gasket is a vital part of the engine. If it’s not working as the manufacturer intended then this can lead to bigger problems. You’ll find this critical seal between the engine block and the cylinder heads. It should be typically made of steel or copper, although some manufacturers use graphite and there are even asbestos gaskets in older cars.

The gasket helps ensure that the engine remains fully pressurised during the combustion process. Remember that the dynamic release of energy when fuel is ignited drives the pistons – so any drop in pressure means a drop in power. Oil and coolant are also supplied to the engine through the gasket, which means that problems with the part could lead to cross contamination between the two fluids – a problematic scenario for any engine.

What causes Head Gasket Failure?

The biggest factor in head gasket failure is heat. If your engine gets too hot, then this will damage the seal. Obviously this varies from make to make and model to model, but if your coolant system is leaking or lacks the required levels of fluid, then this can bring about failure rather quickly. If your engine is made out of aluminium, then thanks to the high expansion rate of this material, it’s likely to put extra pressure on the gasket, meaning you need to be extra vigilant as opposed to someone with a standard steel engine.

The Dangers of Not Replacing a Failed Head Gasket

When you don’t deal with one part failing often it can have knock on effects, damaging other systems in the engine. And yes, they’re going to be expensive to repair. First thing that happens when the gasket fails is that the engine loses pressure, leading to decreased performance and fuel efficiency. However, the big problems start when the coolant and the oil start to mix. Coolant in the oil means that your engine will no longer operate smoothly and oil in the coolant means your engine will overheat. Get it fixed fast.

head gasket

Watch Out for These Signs…

It’s vital to ensure that your head gasket is always operating correctly. As with all part failures there are a number of signs that could indicate malfunction – be on the look-out for the following:

White Smoke from Exhaust

If the coolant and the oil is mixing, then this will cause the coolant to burn off in the engine, resulting in a pale grey or white smoke emanating from your exhaust.

Low Coolant Levels

Again if the gasket is damaged to a point where it’s allowing coolant to leak through into the oil supply, this will mean that your coolant will deplete at a faster level than normal. Check for an elevated engine temperature, as the coolant system won’t be working so effectively either.

Coolant Spots

Another way of confirming that there are problems with the gasket is scouting around your normal parking spots for small pools of coolant. These could well be emanating from a problem with the part and will help confirm your suspicions if this sign appears in conjunction with others on the list.

Radiator Gulping Down Water or Coolant

Coolant problems will manifest in the radiator. If the coolant system is damaged this doesn’t only mean leaks – it means poor heat control. And your radiator will try to compensate for the higher temperature levels by using more water or coolant. Check the levels regularly, and if you find that you’re filling up more than you used to – then head gasket problems could be the culprit.

CO2 in Coolant

Again, if you think your head gasket has issues, then testing the coolant for the presence of CO2 gas will also help you identify this problem by demonstrating that the engine pressure is getting into the cooling system.

Bubbles in the Coolant

Pressure from the engine leaking into the coolant system can also create visible bubbles of CO2 and other exhaust gasses in the fluid, especially if the problems with the head gasket have developed to a particularly serious level. Place a funnel where the radiator cap should be, start the car and watch the coolant as it circulates – if you’re seeing a large number of bubbles, then chances are that this is down to head gasket failure.

Overheating Engine

And if the coolant system is shot, then you don’t have to be a mechanical genius to work out that this problem is likely to manifest as a strong rise in your engine’s temperature.

If you’re consistently finding that even the shortest journey ramps up the heat, then issues with the head gasket could be the answer. Also be aware that issues with the car’s radiator or fan systems could also be the reason why the head gasket has failed.

Milky White Oil

We’ve already explored the contamination of the coolant system when the head gasket fails, causing the oil and air in the engine to mix with the coolant fluid. What about when the coolant mixes with the oil? Obviously this not only degrades the oil’s performance, but you’ll also see a milky sludge on the underside of the dipstick or in the oil filler cap. Leave this problem unattended and it could lead to your engine’s bearings failing too.

Fouled Spark Plugs

When coolant burns in the combustion chamber, this creates deposits around the electrode and ground-strap on your spark plugs. Whilst this may point towards head gasket failure, there are other problems that can cause such a build-up – but when taken into account with other symptoms on this list it can help you pin down gasket failure.

Low Cooling System Integrity

Issues with the head gasket are likely to lead to a loss of pressure from within the coolant system, as fluid leaks through fissures into the oil and engine space. Perform a leak down test to see how much air is held by your engine – and how much escapes if you are noticing pressure drops in the coolant system and want to investigate further.

Loss of Power

The head gasket is responsible for keeping the engine pressurised and when it breaks or fails then the pressure comes rushing out of the engine. With the combustion energy no longer contained within, the engine’s performance will dramatically drop, and you’ll notice that the car isn’t running so smoothly either.

Be Vigilant

A blown head gasket is one problem you need to take seriously. If you have any kind of suspicions about your car, then get out to the mechanics and get it checked out. Our list contains a number of signs that will show themselves and a few that require a little more investigative work – and can almost be used as tests to confirm failure. So when a few of these signs appear together don’t hesitate in booking that slot at the garage.

This entry was posted in Maintenance and tagged , on by Justin Smith.
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About Justin Smith

As the man at the helm of BreakerLink, it is no surprise that its Director, Justin Smith, has always had a keen interest in cars, bikes and most things wheeled. Having spent over two decades in the car parts industry, Justin combines his passion that since 2002, has successfully united those looking for new and used car parts with the breaker that supplies them. Follow Justin on LinkedIn.

Disclaimer: These articles are for guidance purposes only. If you have any questions regarding any matter relating to your vehicle we would recommend that you seek the advice of an appropriate professional. We accept no responsibility or liability should you suffer financial or personal damages in relation to the advice stated on this website.