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Sometimes your engine heats up and reaches critical temperatures when you’re driving. Normally, turning off the air conditioning would help in this scenario, but what if your engine overheats even if you haven’t turned on the AC?

Engine Hot, AC Off: What Does That Mean?

If you’re wondering what a hot engine means if the AC is off, then there’s a good chance that your vehicle’s got a serious problem. It might have broken parts due for replacement, or there could be a shortage of coolant brought about by contaminants or a leak in the hoses or the water pump.

This is particularly problematic since hot engines are a lot more prone to overheating. If an engine overheats the odds of it breaking down and sustaining permanent damage increase exponentially.

Potential Causes Of A Hot Engine If the AC is Off

If you’re wondering how your engine gets so hot even if the air conditioning is off, then there are many explanations as to why. Usually, it’s due to a lack of coolant. In other cases, the culprit for an overheating engine is broken parts. Here are some of the potential causes of overheating engines.

Broken Thermostat

broken thermostat causing hot engine
If the thermostat breaks, then your engine will have a more difficult time cooling itself down since coolant won’t be able to flow in when it needs to.

The thermostat is responsible for regulating the temperature of your vehicle’s heat by controlling the flow of hot water and coolant through the radiator. If the thermostat breaks, then your engine will have a more difficult time cooling itself down since coolant won’t be able to flow in when it needs to. Without enough coolant, the engine overheats and your vehicle becomes susceptible to permanent damage.

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Damaged Water Pump or Hoses

If the water pump or the hoses are damaged in any way, coolant might have a hard time flowing throughout the engine to absorb heat. This makes your engine more likely to overheat since there’s nothing to help regulate the temperature.

Malfunctioning Radiator

If your engine is prone to overheating but coolant levels are normal and there don’t seem to be any leaks, there’s a good chance there’s something wrong with the radiator.

The radiator helps coolant cool down after it’s absorbed a lot of heat from the engine. If the radiator burns out or takes any external damage via an accident, it might stop functioning, preventing the coolant (and your engine) from cooling down.

Low or Contaminated Coolant

If you fail to top up your coolant or if any leaks cause your coolant levels to drop at alarming rates, your engine will be more prone to overheating. Bear in mind that it’s also possible for coolant to get contaminated by water and other substances that can negatively impact its ability to absorb heat. Even if your coolant reserves are high, it’s important to replace your coolant every once in a while.

What to Do When the Engine Overheats

If you want to mitigate the damage caused by an overheating engine and prep your vehicle for servicing, follow these steps carefully.

Turn Off the Air Conditioning

As mentioned previously, turning on the air conditioning while the engine has trouble regulating temperatures puts extra strain on the latter. This happens because the AC draws power from the engine shaft, and this increases the overall heat buildup in your engine. As a result, your engine becomes far more likely to overheat. Fortunately, disabling your AC will minimize the stress on your engine.

Activate the Heater

After turning off the air conditioning, you need to pull over. If that’s not possible, then you need to activate the heater and drive until you can find a place to stop. This will draw heat away from the engine and redirect it toward the rest of your vehicle. The heater accomplishes this by using the heat absorbed by the coolant and redistributing it throughout the cabin.

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It’ll be hot and uncomfortable, but at the very least you can open your windows. By redirecting the heat from your engine, you can prevent it from taking any additional damage from overheating. Once you’ve turned on the heater, keep driving until you can find a spot to pull over.

Pull Over and Shut Off Engine

Pull over the side of the road and shut off your vehicle’s engine as soon as you’re able to. Driving with an overheating engine can cause serious and costly damage, so you want to minimize driving it as much as possible. After turning off the engine, give it some time to cool down on its own. You can even add coolant to the engine after it returns to a more stable temperature.

Have Your Vehicle Towed to a Repair Shop

Once the temperature of the engine stabilizes, it’s important to bring it to a repair shop as soon as possible. Since driving your vehicle after it overheats is a bad idea, your best bet would be to call for a tow and get your engine checked out by a professional.

Once your vehicle gets inspected, mechanics should be able to single out the cause of an overheating engine and repair or replace any broken parts.

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How to Prevent Your Engine From Overheating

Knowing what to do to keep your engine’s temperature stable is just as important as knowing what to do when your engine overheats. If you want to know what steps you can take to protect your engine, read on.

Watch the Temperature Gauge

The best way to keep your engine at a stable temperature is to regularly check the temperature gauge. Engines typically overheat at temperatures of around 220 degrees Fahrenheit. If the reading on the gauge goes beyond that, it’s a good idea to stop your vehicle.

Park in Shaded Areas

Hot weather and harsh sunlight can heat your engine even when you’re not driving. Because of this, it’s a good idea to park away from direct sunlight or avoid driving in the heat for extended periods.

Top Up Your Coolant

Checking your coolant level and topping it off whenever needed is the best way to minimize the odds of your vehicle overheating. It’s a good idea to bring extra bottles of coolant with you just in case you need to add some to your vehicle.

Regular Maintenance

Following your vehicle’s service schedule is one of the best ways to guarantee that your vehicle remains in peak condition. By having a professional run diagnostics, replace any broken parts, and replace fluids like engine oil and coolant, you can make sure your vehicle works smoothly and lasts as long as possible.

About The Author
CarParts Research Team
Written By Research Team

Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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