A broken car heater may be an inconvenience in the colder months, but will it lead to MOT failure? 

Read on and find out whether a broken car heater will result in MOT failure, how a car heater works, and what causes a car heater to break in the first place.  


Will a Faulty Car Heater Lead to MOT Failure?

Whilst a faulty or broken car heater can be annoying, it will not result in MOT failure, as it is not included as one of the main checks during the test. 

That being said, you should not ignore any issues with your car heater for long.  

If you have checked and topped up your coolant levels and are still experiencing problems with your car heater, be sure to book an appointment with a skilled garage so that they can fix this for you.  


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General Repair


How Does a Car Heater Work?

Your car heater uses coolant to warm up the vehicle’s interior.

The engine will heat the coolant to a high temperature, before the coolant is pushed through the heater core. Air can then be pushed through the heater core, which will cause hot air to blow into the car.  

When you turn on your car, you will probably notice that the air feels cold, as the engine needs more time to warm up and heat the coolant.  


Why Is My Car Heater Not Working?

If your heating system is struggling to work properly - perhaps no hot or cold air being blown around the car - then there could be a faulty blower motor 

Alternatively, your vehicle may be low on coolant. Without enough hot liquid in the heater core, the air may come out cold.

However, if the issue is a faulty heater fan, then even if the car heater is working properly, the hot liquid will only get as far as the heater core.

You can top up your coolant levels or ask a mechanic to do this for you.

A faulty heater fan could be the result of a mechanical or electrical problem, and will need to be looked at by a professional garage.  

If your car heater is unresponsive, then the issue could be a damaged or short-circuited wire, or even a blown fuse.

The issue could also be a faulty thermostat which, if corroded or aged, can stop coolant from reaching the radiator. This can cause your engine to overheat, which can cause irreversible damage and be costly to fix.  


We hope that you have enjoyed learning about whether a broken car heater will result in MOT failure.

If your car’s current MOT certificate is soon to expire, remember to book your MOT test in good time.  


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If you would like to learn more about MOT testing, we have plenty of interesting blogs for you to read.