Car AC Off Due To High Engine Temperature : Meaning, Causes & Fixes

AC off due to high engine temperature

Many times, “AC off due to high engine temp” is a serious problem in vehicles. When you are enjoying your journey by running the AC in your car, suddenly you see that “AC off due to high engine temp” sign on the dashboard of the car, and the AC of the car gets turned off.

In this post, we will discuss in detail the problem of “AC off due to high engine temp”. Like Causes and how to fix it.

What Does “AC Off Due To High Engine Temp” Mean?

AC off due to high engine temperature means that the vehicle’s ECM detects excessive engine temperature and then displays a warning message “AC off due to high engine temperature” on the dashboard. AC shut-off due to high engine temperature is caused by the vehicle’s radiator electric fan failing or other cooling system components malfunctioning.

When the engine’s cooling system fails or a component in the cooling system is defective, the engine temperature rises excessively. Which is detected by the ECM of the vehicle through the temperature sensor.

The vehicle ECM may disable the air conditioning compressor to prevent engine overheating and possible damage. This is done to reduce the load on the engine, as the air conditioning system requires additional power from the engine to operate.

Possible Causes of ”AC Off Due To High Engine Temp”

Common causes of AC shutting down due to high engine temperatures include insufficient coolant level, blockage in the cooling system, a faulty thermostat valve, a faulty radiator fan, serpentine belt issues, a bad water pump, a faulty temperature sensor, or engine overload.

You will learn in detail the common causes of AC shutting down due to high engine temperatures so that you can work on emergency repairs when this problem occurs.

1. Insufficient Coolant Level

A low coolant level or a coolant leak can result in higher than normal engine temperatures, which can lead to engine overheating. This causes the vehicle’s ECM to automatically turn off the AC system.

2. Cooling System Blockage

Different components are used in the cooling system of the engine. Such as the radiator, coolant hoses, or thermostat. A blockage in any component of the engine’s cooling system can obstruct the flow of coolant to the engine. And this can cause the engine to overheat. The vehicle’s ECM may turn off the AC due to a high engine temperature.

3. Faulty Thermostat Valve

The thermostat valve plays an important role in maintaining the normal temperature of the internal combustion engine in vehicles. When the thermostat does not open and close properly, it can restrict coolant flow to the engine and may prevent the engine from maintaining a stable temperature, causing the vehicle’s ECM to turn off the AC due to the high engine temperature.

4. Faulty Radiator Fan

A radiator fan in a vehicle’s engine cooling system helps to cool the engine by drawing air through the radiator, thereby maintaining a constant engine temperature while running. If the radiator fan is not working properly, then there is no air flow to the radiator, which causes the engine temperature to rise. The vehicle’s ECM turns off the AC when the engine temperature rises above a certain point.

5. Serpentine Belt Issues

The serpentine belt drives the engine’s water pump, which circulates coolant through the water pump to the engine’s cooling system and maintains a constant engine temperature. If the belt is loose, worn, or broken, it can affect the functionality of the water pump, potentially causing the engine to overheat and the AC to shut off. Often, the serpentine belt also drives the radiator fan in older vehicles.

6. Bad Water Pump

The water pump serves to drive the flow of coolant into the engine of the vehicle, thereby maintaining a constant engine temperature while it is running. But sometimes, a bad or broken water pump can block coolant flow to the engine and for this reason, the engine starts at a high temperature. The ECM turns off the AC due to high engine temperatures.

7. Faulty Temperature Sensor

A temperature sensor located in the vehicle’s engine cooling system monitors the engine temperature and reports the temperature to the vehicle’s ECM. But a bad temperature sensor can provide an incorrect engine temperature reading to the ECM, which will signal a high engine temperature to the ECM and cause the AC to shut off.

8. Engine Overload or Weather Effects

Sometimes driving the vehicle continuously under heavy loads, such as pulling a trailer or lifting a heavy load, can put extra strain on the vehicle engine, causing high engine temperatures, or sometimes driving the vehicle to an extremely hot location.

9. Engine Oil Issue

In vehicles, oil provides lubrication to the engine, thereby absorbing the heat generated by the friction of the engine’s internal parts. But in many cases, low or run-out engine oil can also cause a high engine temperature, causing the vehicle’s ECM to shut off the AC, indicating a high engine temperature.

10. Bad AC Compressor

In many cases, a bad compressor on the vehicle’s AC can also cause high engine temperatures. A bad AC compressor or compressor bearing can create additional stress on the engine when the pistons are damaged. Due to this, high temperatures start due to overloading of the engine.

How To Fix “AC Off Due To High Engine Temp”

To fix the problem of the AC going off due to high engine temperature, you should follow the following steps: As if:

1. Safely Stop & Examine The Vehicle

If the engine temperature is rising while the engine is running and the AC is turned off, let the engine idle and wait for the temperature to return to normal. After this, the reasons for the high temperature of the engine should be investigated. The engine should be allowed to cool before any troubleshooting or repairs are made.

2. Check Coolant Level

Open the hood of the vehicle and check the coolant level in the radiator or coolant reservoir. So the reason for the low coolant should be investigated. In many cases, you may have a coolant leak or insufficient coolant, causing a high engine temperature. Top up the coolant level according to the vehicle manufacturer’s recommendations.

3. Inspect For Coolant Leak

Troubleshooting this problem should include checking for coolant leaks in the vehicle’s cooling system, such as puddles under the vehicle or wet spots on hoses and connections. If you find a coolant leak in the vehicle’s cooling system, the first thing to do is repair the leak. As this can be the main cause of excess coolant loss and engine overheating.

4. Check The Thermostat

The thermostat valve plays a vital role in the cooling system of any vehicle with an internal combustion engine and regulates the engine temperature. If the engine is getting high temperatures, the thermostat should be checked to troubleshoot this, and if the thermostat valve is faulty, the best step is to have it replaced by a qualified vehicle mechanic.

5. Check Cooling System

The radiator, radiator hoses, and water pump should be checked for any blockages, leaks, or defects in the vehicle’s engine cooling system. Because a blockage or leak in the cooling system can cause high engine temperatures, Therefore, after checking, clean or repair the cooling system as necessary.

6. Check Radiator Fan

A radiator fan is an important component of a vehicle’s engine cooling system. Therefore, when this problem occurs, make sure that the radiator fan is working properly. To check the radiator fan, start the engine and observe until the fan runs. If the radiator fan does not engage or runs slowly, there may be a problem with the fan motor, relay, or temperature sensor. You should seek the help of a professional vehicle technician to diagnose and repair it.

7. Check Serpentine Belt

Inspect the timing belt for signs of wear, damage, or loosening when the vehicle’s engine is at a high temperature. If it appears worn or damaged, you should consider replacing the serpentine belt according to the manufacturer’s recommendations. Because a loose serpentine belt can disrupt the functioning of the water pump. However, you may need to adjust the tension or replace the belt tensioner if there is a loose belt.

8. Check Temperature Sensor

A bad temperature sensor in a vehicle’s engine cooling system can provide inaccurate readings, indicating cooling system problems. This can cause the vehicle’s ECM to receive incorrect engine temperature signals, and the ECM may turn off the AC. Therefore, should this happen, a qualified mechanic should get the temperature sensor tested for functionality and replaced if necessary.

9. Do Not Overload The Engine

If you frequently drive under heavy loads or tow heavy trailers, consider downsizing or upgrading to such a vehicle. Because overloading the vehicle puts excessive stress on the engine, which puts the engine at risk of overheating, So always do not let the engine overload.

Can “AC Off Due To High Engine Temp” Be Dangerous?

If the engine temperature of your vehicle is continuously rising to a high level and the AC is shutting down, And you’re ignoring it, so it’s really a concern. Because driving a vehicle with an overheating engine can potentially cause serious damage to engine components and, in some cases, even lead to an engine seizure.

  • Engine overheating causes serious damage to various engine components, such as the cylinder head, gaskets, pistons, and valves. And this damage is expensive to repair, as it may require the dismantling or replacement of the engine.
  • Constant overheating can lead to breakdowns, leaving you stranded on the road.
  • An overheating vehicle engine can also affect the vehicle’s control systems. Such as power steering and braking systems. This can make it more difficult to control the vehicle safely.
  • Excessively high engine temperatures may increase the risk of fire. Leaking fluids, such as coolant or oil, combined with heat can create a dangerous situation.

What To Do When The “AC Off Due To High Engine Tempe” Symptom Appears

Whenever you are driving and suddenly you see the “AC off due to high engine temperature” sign, the first thing you should do is not to panic and stop the vehicle at a safe side of the road.

  • After this, you turn on the emergency lights so that other vehicles know that there is something wrong with your vehicle and can prevent a collision.
  • Never shut down an overheated engine. Because this can cause the engine to seize. In this case, let the engine run at idle to allow the engine temperature to return to normal. However, you can also sprinkle water carefully for this.
  • Check your temperature gauge to make sure it’s normal and that there’s no damage to your engine.
  • Check your engine’s coolant reservoir for possible coolant leaks, and also check your car’s radiator and cooling fans.
  • You should handle this carefully and avoid touching any hot components or water to your skin. Because overheated components or coolant can harm you.
  • Keep the engine running at idle to allow the radiator fan and water pump to quickly bring the engine temperature back to normal and cool the engine.
  • After the engine has cooled down, you can take the vehicle to an automobile repair shop for a proper diagnosis of the related problem.

How To Prevent This From Happening Again?

To prevent this problem from happening again, you can follow the following steps:

  • To prevent this problem, at least once every 10 to 15 days, turn on the AC for some time, even when it is not needed, so that the AC compressor can work smoothly and the flow of coolant can flow smoothly.
  • Avoid using only water in the engine’s cooling system. This can lead to the corrosion of cooling system components and cause blockages. Hence, always use high-quality coolant fluid in the cooling system.
  • The engine’s cooling system must be periodically checked for leaks and damaged components.
  • The engine coolant level should be checked and replaced if it is low.
  • Avoid operating the vehicle with a loose or damaged serpentine belt. Because a loose serpentine belt may disrupt the functioning of the water pump and cause the engine to overheat,
  • Engine oil should be checked regularly and changed promptly.


Q. What if AC is on but not cooling?

If your air conditioner is running but cool air is not coming from the AC vents, a problem could be a blocked condenser or coil. Apart from this, low refrigerant, compressor failure, or radiator fan malfunction can also cause this problem.

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