Can a bad AC compressor cause a car to overheat?

There are several reasons why a car overheats, a bad AC compressor is certainly one of those reasons. Whether it be an issue with the cooling system, something wrong with the fan, or a faulty water pump, any of these can drastically increase the engine temperature.

Be sure to take your car in for a proper inspection as there are many different reasons as to why this happens. If you don’t find the right culprit, the issue might persist and cause additional damage over time which will put a strain on your engine.

Engine heat management is important if you want your engine to always perform at its finest. Whenever the temperature increases, the combustion process is not as refined which results in loss of power among many other things.

The most frequent reason for overheating is AC compressor overload or simply a bad cooling system. Besides these, a faulty engine coolant sensor and a faulty fan are also known to cause such issues. Be sure to check all the components and all the fluids to make sure you find the right culprit.

AC Compressor Overload – The most common reason for overheating

Between all the reasons listed here, AC compressor overload is quite possibly the reason why your engine overheats. The AC compressor requires lots of power to operate as intended, that’s the reason why the AC system draws considerable amounts of energy from the engine itself.

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Of course, this might not be as noticeable while driving a car with a bigger, more powerful engine, but if you’ve ever driven a smaller car with a weaker engine, chances are that you have felt the loss of engine power the moment you turn on the A/C.

As such, these two important components have to work in tandem, and when you turn on your A/C, the compressor draws power from the engine to turn the cylinders inside the compressor that compress the refrigerant.

As the engine turns, the compressor turns as well. If the compressor is unable to take the strain for whatever reason, it starts bottling down, and it does not spin in tandem with the engine. If this persists, it causes the engine to overheat.

Bad cooling system – Commonly known to cause engine overheating

When the car’s engine, and many other parts spin, turn, or do whatever they need to do, they create energy and friction. Some of those parts spin faster than others, and some of them are bigger than others. Such energy results in increased temperatures, and they ought to be cooled down.

This is where the entire car cooling system comes in with a set of refrigerators, fans, coolant liquids, sensors, and whatnot. All of these components are tasked with heat management and keeping all of the aforementioned components in their optimal temperatures for efficiency’s sake.

The role of the cooling system in this situation is to keep the A/C condenser cool, and if for some reason your cooling system is not working as intended, the temperature will rise and eventually lead to engine overheating.

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Such issues are often caused by pipe and/or refrigerator clogging. Be sure to take your car in for an inspection because a bad cooling assembly might ruin more than just the A/C system. Proper heat management is paramount for your car.

Defective engine coolant sensor/fan – Sometimes known to cause engine overheating

It’s not all that common that a coolant sensor fails, but it is possible. This happens if the temperature readings are not correct while the A/C is working. More often than not, this also causes inaccurate temperature readings on the dashboard.

To remedy this, make sure to check the thermostat, if the sensor is not measuring the correct temperature, it is essential for you to figure that out as soon as possible. A professional mechanic should easily fix this, if not, you might want to look into replacing the entire sensor.

Besides a defective engine coolant sensor, a faulty fan is also sometimes known to cause engine overheating while the A/C is on. If your car experiences temperature increases while idling or driving at lower speeds, a faulty fan is probably the reason why.

If the airflow is somehow blocked or the fan itself is broken, your car is going to overheat. Such problems usually result in fan switch failures, and if this happens, your car could overheat in a matter of moments.

FAQ Section

How can I get rid of engine overheating?

Be sure to check a few vital engine cooling components and liquids such as the water pump, the radiator, the A/C compressor, refrigerant, the A/C condenser, and even the antifreeze liquid. The water pump is tasked with moving the water around the engine in an effort of cooling it down.

More often than not, a faulty A/C compressor is the most common culprit with A/C defects, so make sure you inspect it before you do anything else. The best way to do this is to take your car in for an inspection at a licensed professional mechanic.

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Is it bad to turn on you’re A/C before you turn on your car?

Contrary to popular belief, there is no need to start your A/C after you start your engine. Most modern car electrical systems are more than capable of taking the load, but it is not a good idea to keep you’re A/C running for too long without the engine running.

However, if your electrical systems are not running as intended, or your battery is weak or old, starting your A/C without the engine running might just shorten the battery’s lifespan. Your electrical and mechanical car components should work in tandem.


What does an A/C thermostat do?

The air conditioning thermostat is tasked with regulating the fluid temperature in the radiator hoses. A bad thermostat causes power loss and temperature fluctuations. The greatest possible issue is when your thermostat is unable to read the temperature at all, and it stops regulating the temperature entirely.

Even the coolant that goes through the engine itself is regulated by this thermostat which means that if it goes bad, overheating is a likely possibility.

Marko Mikulic

Why do you love writing about cars? I love writing about cars as cars are a huge personal interest of mine. I was raised in a car enthusiast community and ever since I was young, I always wanted to do car-related work.

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