Why Does The AC Shut Off When The Car Overheats?

Do you know what it means when the flashes on your dashboard say AC off due to high engine temperature? If the warning signal shows up while driving, it may indicate a problem with the …

ac off due to high engine temp

Do you know what it means when the flashes on your dashboard say AC off due to high engine temperature? If the warning signal shows up while driving, it may indicate a problem with the car’s engine. At this point, you should immediately listen to your vehicle, so stop the engine and let it cool for some time.

What Does It Mean When Your Car Says “AC Off Due To High Engine Temperature”?

The warning signs saying “Engine hot, AC off” on the dashboard when driving slowly or while likely idling means the problem is with the engine cooling unit. It also indicates issues with the radiator and cooling fans. Also, check the leakage in the hoses and vents. On top of all, this warning sign also draws attention to coolant leaks.

Following is a detailed overview of the possible causes of an overheated engine and AC shut-off.

1. Malfunctioning Thermostat

“AC off, engine hot” is a warning message that appears when the car engine gets excessively hot, and the cooling fan fails to function correctly. It may be due to the old worn-out thermostat that remains open all the time and prevents the engine from working at its optimum temperature. The issue can be resolved by replacing the old thermostat with the new one.

2. Compressor Overload

The air conditioning system draws a huge amount of power out of the engine, leaving the compressor overloaded beyond its capacity. On the other hand, the faulty air compressor puts extra load on the engine and forces it to bear the rotational load. So the malfunctioning compressor that deposits all the load on the engine could be a potential reason for “AC off, hot engine” flashes on the dashboard.

3. Failed Radiator Cooling System

The radiator cooling system is the next system that needs to be checked when the AC shuts off due to overheating of the car engine. The main objective of the cooling system is to keep the air conditioning condenser at a lower temperature, which usually tends to heat after you switch on the AC. The raised engine temperature can be due to the blocked condenser fins, a defective condenser fan, or a faulty water pump that failed to circulate the coolant properly.

The inefficiency may also cause by the corrosion occurring in the radiator tubes, resulting in obstruction in coolant flow.

4. Blown Head Gasket

The Head gasket aims to protect the cylinder from coolant infiltration or engine oil. Overheating, car vibrations, and mechanical forces may displace the head gasket. The situation is called a blown head gasket, which can cause flashes of “AC off, engine hot” on your dashboard.

What to Do When AC off Due to High Engine Temp?

When you see the ‘AC shuts off due to high engine temperature’ flashes on your dashboard, make sure to do the following things:

  • Analyze the vehicle temperature gauge to protect your engine from any underlying risks.
  • Immediately slow down and pull over the vehicle, and shut it down.
  • In case of a malfunctioning thermostat, you need to replace the defective thermostat with the new one.
  • Overheating could be due to trapped air in the cooling system; flush it to release extra air.
  • Clean the radiator and install an air pressure gauge to maintain its airflow.
  • If you have the coolant on board, add it to the refrigerator.
  • Inspect the radiator and add water if it is dry.
  • Make sure all vents and hoses are clear.

If you’ve checked all the components mentioned above and the car still shows the warning sign, contact a mechanic to check your vehicle further. Before driving, make sure the engine and AC are both working properly.

Other Similar Problems
Car Temperature Gauge Goes Up and Down While Driving
Car Overheating Then Going Back to Normal
Car Overheats When Idling


Can I Drive My Car If the Ac shuts off due to Hot Engine?

The answer to the question is “No.” You should immediately stop driving and let the car cool down for some time. And try to find the issue considering the causes mentioned above. If you successfully detect the underlying cause, try to fix them using above mentioned DIY methods.

After fixing the issue, ensure the engine and AC are both working correctly; otherwise, go to a professional mechanic and check your car thoroughly. After the detailed professional checkup, you can continue driving without risking your life. Sometimes, the issue may be due to low coolant or an air pocket. In that case, you shouldn’t be worried. But try to inspect if there are any other issues. 

What Does It Mean When Your Car Says Ac Off For Engine Protection?

Car AC shuts off due to high engine temperature means that the Engine Control Unit of the car detects overheating in the engine. Engine overheating can damage the engine if the cooling system is not efficient enough to dissipate this heat. So to reduce the engine load and more heat generation by the AC, the ECU turns the AC off. 

The most common causes of the “AC off, engine hot” warning sign, are listed below:

  • Failed Thermostat
  • Obstruction in the cooling passages
  • A leak in the drive belt valve seal
  • Loosened driver gasket seals

How Do You Fix High Engine Temp?

Here are some ways by which you can quickly fix AC off due to high engine temperature:

  • Let the engine cool for 20-30 minutes.
  • Change the blown head radiator gasket.
  • Replace the malfunctioning thermostat.
  • Disconnect the battery for a short time, then reconnect it.

Final Thoughts

If you can detect the underlying reason, you can quickly fix the problem. Nevertheless, this is one of the most common issues of vehicles. On top of it, with proper care and regular maintenance, you can avoid this situation. If the engine gets hot when the air conditioner is off, it depicts an issue in the cooling system. On the other hand, if the engine gets hot when the air conditioner is on, it shows that the problem is in the electric cooling fan of the air conditioner.