Have you ever had your AC turn off due to the car overheating like I have? It’s a sickening feeling to watch that temperature gauge rise as steam begins to boil out of the engine compartment. When that happens, is there anything you can do, or do you immediately call a tow truck?
When you see the warning sign on your car’s dash “AC off due to high engine temp,” you should find a safe place to pull over as soon as possible. The engine needs to cool off before more damage happens. An engine that is overheating can lead to huge repair bills if you continue to drive it while it’s still hot.
There are several factors that can cause this warning light to come on. Keep reading as we go over the possible issues that will cause the AC to turn off when the engine temp gets too high. We’ll also explain what steps you need to take if, and when this happens to you.
Why Does the AC Turn Off With High Engine Temp and What Does it Mean?
The air conditioning system, especially the compressor, puts a lot of strain on the engine while it’s running. When the car’s engine is beginning to overheat, the car’s computer knows to drop non-vital functions to try and reduce the heat and engine strain.
This warning light means there is something mechanical in nature that is not working properly and your engine is getting too hot. When an engine gets too hot, it can seize up, and cause catastrophic damage. The car’s computer is trying to prevent that damage by turning off the AC.
Now, let’s go over what can cause your car’s engine to overheat.
What’s the Cause of an Overheating Engine?
When your car is working properly, it will run at the proper temperature. When it starts to overheat, it’s usually a result of a failed part or a leak in the coolant system. The following problems are the most common issues you may come across.
Problems With The Radiator Cooling Fan
The fan works two ways to cool off your car. It draws in cool air to reduce the temperature of the coolant flowing through the radiator, and the air then blows over the engine, which helps to cool it off as well. If your car is overheating, and the fan isn’t running to help reduce the heat, it’s a good bet that the fan needs to be replaced or fixed. It could also be the reason why your AC stops working when it’s hot outside.
Blown Head Gasket
The head gasket is a vital piece that is constantly put under tremendous stress. Extreme heat and pressure can eventually cause these gaskets to fail. When they do, you can lose coolant, the oil and coolant will mix, or it will leak oil from the engine.
All of these can cause your car to overheat. If you notice muddy looking oil, or oil in the coolant you have a bad head gasket and will require a mechanic to fix it.
Malfunctioning Temperature Sensor
Most cars have an Engine Coolant Temperature sensor (ECT) which signals when the fan should come on and adjusts other parts of the car. When it fails, it could prevent the fan from coming on and lead to your car overheating.
You Have a Bad or Clogged Thermostat
The thermostat adjusts the flow of coolant inside the engine. When it heats up enough, the thermostat opens to allow more coolant to reach vital engine parts. If it gets clogged or fails, it can cause the engine to overheat.
Low Coolant Levels
The coolant circulates through the radiator and the engine. This cycle takes heat from the engine, cools it off in the radiator, and brings cooled liquid back to the hot engine. When there isn’t enough coolant the engine will surely overheat.
Low Coolant levels can also cause other annoying problems in your car such as blowing cold air when idling and hot air when moving.
The Correct Way to Deal With an Overheating Engine
Turn Up The Heat
One way to help cool the engine is to turn on and turn up the heat. The heater works by blowing air across the heater core, which circulates coolant, exactly the way the radiator works. By doing this you help to cool the engine more.
Slowly And Carefully Pull Over
Put on your hazard lights and pull over when it’s safe to, but try to pull over as soon as possible. You need to let the engine cool off before traveling any further than absolutely necessary.
If it’s just not possible to pull out of traffic yet, turn on the heat to try and help cool the engine until you can turn it off.
Turn Off The Engine
Once you get to a safe pull-off spot, turn off the engine so it doesn’t continue to overheat. You may want to leave the key in the ignition for a few minutes if you hear the radiator fan running. It will continue to help cool the motor even when the car is turned off.
Keep The Hood Closed For Some Time
Depending on how hot the engine is, the hood could also be painfully hot. Feel around the hood and latch without touching it first, and only open the hood if you can touch the hood without burning yourself.
Also, don’t open the hood if you see steam coming from the engine department. Steam will cause severe burns much faster than touching a hot surface, and faster than boiling water. Keep everything closed until it’s safe to open it
Check The Engine Coolant Level
Always wait until the engine has cooled before trying to check the coolant level. You should never open the coolant or radiator cap when the engine is hot because it is under tremendous pressure and can boil out or steam up and cause extreme burns.
Seek Professional Help
Chances are if your car overheats while you’re on the road, you’ll have to get someone to fix it for you. Adding coolant and/or water may help you get home, or to a service station, but the cause still needs to be fixed. Call a tow truck if your car continues to overheat after pulling over and letting it cool off.
Can You Still Drive When Engine Hot AC Off Error
Don’t attempt to drive your car until it has cooled off. If you had low coolant, once you refill it, that may have fixed the issue completely. If something else is the culprit, you should get it fixed before driving your car again.
There may be a time when you don’t have a signal, or you’re very close to home. In that case, you can drive your car slowly, but only after it has cooled off, and you’ll have to stop to let it cool off again when the temperature gets too hot.
Many times, proper maintenance can help you avoid engine overheating.
Proper Maintenance is Key
Schedule Regular Maintenance Services
The coolant should be flushed and replaced about every 30,000 miles, or every two years. Rust and deposits can build up, so to keep it fresh, clean, and in proper working order replace it occasionally.
This coolant flush can also help you or your mechanic notice any hoses that need to be replaced or coolant leaks that were previously undetected.
Pay Attention To The Temperature Gauge
Under normal driving conditions, the temperature should rest somewhere in the middle of the gauge. In the heat of summer, it may get a little warmer, and in winter, it may run a little cooler. If you notice it creeping into the red, you should try and pull over to let it cool off.
When you’re able to, have the car checked to see if there’s something causing it to start to overheat.
Do Not Leave Your Car In The Sun For Extended Periods
In the middle of summer, try to park your car in the shade if possible. The added heat from the sun can create an overheating issue.
Very slow-moving traffic can cause your car to overheat as well. When stuck in traffic, you may want to turn the engine off if you’re not going anywhere. A car in idle has a harder time cooling off than a car that’s running.
Drive With Extra Coolant
Keeping an extra gallon of coolant in your trunk isn’t a bad idea. You never know when you might need it. Also, check your coolant levels before you drive off. You may be low and don’t know it, then you’ll have to wait for the car to cool before you can add more.
Should I run my vehicle while overheating?
You should pull over when it’s safe and let your car cool off when it starts to overheat. Continuing to drive your car when it’s overheating can cause catastrophic engine failure.
How bad is an AC engine light error issue?
Assume it’s bad and pull over when you can, and get it checked by a mechanic as soon as you can. It may be something as simple as a bad sensor or low coolant, but if you continue to operate your car when it’s overheating, you could cause major damage.
When the AC turns off because of high engine temperature it can be from several different issues. These could include a bad ECT sensor, low coolant, a broken radiator fan, or a blown head gasket.
When you get that warning on your dash, pull over when you’re in a safe area and let the car cool off. If you’re close to a service station or your home, you might be able to drive there as long as you pull off and let the car cool if it gets too hot.
Then get the repair fixed when you know what the problem is. You don’t want to continue driving your car when it’s overheating, it can cause a major engine problem if you do.