The Head Gasket Killer: A Bad Thermostat

A thermostat is a small but important part of your car’s cooling system. If it fails, the engine will overheat and eventually blow the head gasket. A blown head gasket can cause major damage to not only your engine but also other components, such as the radiator and hoses.

What is a head gasket? A head gasket seals the engine’s combustion chamber and prevents coolant from leaking into it. It also keeps oil from leaking out of the engine block. How a thermostat can cause your car to blow its head gaskets!

How Does a Thermostat Blow a Head Gasket?

A blown head gasket can happen for any number of reasons, from low-quality parts to old age. One particular reason is a stuck closed thermostat that prevents the coolant flow through the radiator, causing engine overheating. The extreme heat can warp the cylinder head, which leads to a blown-up head gasket.

If you suspect a faulty thermostat or the coolant temperature is increasing, simply pull the vehicle over and turn off the engine. You should then check the fluid level in the radiator, as well as examine it for any coolant leaks.

A blown head gasket. (Credit: Tony Harrison / Flickr)

If there are no leaks or apparent signs of problems with either of these components, you can get back on the road by turning on just enough air conditioning so that you don’t need to use heat while driving again until you reach a service station where you can take steps to fix what’s wrong.

Head Gasket Failure Symptoms

When the head gasket fails, the car will show several symptoms. Be alert if you experience any of these warning signs while driving:


Lack of coolant in the radiator and constant running or cycling of the engine to maintain temperature leads to overheating. If you’re experiencing these issues with your vehicle, it may be time for an inspection by a professional.

The other possibility is that air is getting into your cooling system. This can happen if sealings around cylinder heads or the radiator have failed.

No Coolant Flow

Thermostat problems can make the coolant stop flowing. It could also happen because of worn-out head gasket sealings.


How to Prevent and Fix the Problem

There are some simple things you can do to keep your car’s head gaskets in good condition, such as checking the coolant level and making sure that it isn’t low. Examine thermostat failures by looking at the temperature gauge on the dashboard when driving. If it’s not registering accurate temperatures, then chances are that there is a problem with your thermostat.

You should replace your car’s head gaskets with new ones if the overheating symptoms persist. You can also ask for professional help from an auto repair specialist.


A faulty thermostat will cause the coolant to overheat and blow a car’s head gasket. Several things can go wrong regarding the heating and cooling system, so you should try to keep up-to-date with its maintenance. If it’s necessary, replace the gasket with a new one or have an auto repair specialist help.