Causes and Solutions for Overheating Engine Temperature When Using Air Conditioning
2 Answers
Causes and solutions for overheating engine temperature when using air conditioning are as follows: 1. When turning on air conditioning: Cause: The thermostat opening is not increased or has reached maximum but temperature remains high. Solution: Improve cooling capacity. 2. After turning on air conditioning: Cause: Increased load leads to higher heat dissipation, naturally raising coolant temperature. Solution: Maintain original equilibrium temperature by increasing thermostat opening. 3. Other causes: (1) Insufficient coolant: Leakage in cooling system causes low antifreeze level, leading to temperature rise. If antifreeze level is low, check for leaks. If no leaks found, promptly add same type of antifreeze. Do not add tap water or other antifreeze types to avoid dilution/precipitation causing failure. (2) Thermostat failure: If temperature remains high after increasing thermostat opening, consider replacing the thermostat.
I've experienced this before—stuck in traffic on a hot summer day with the AC on, watching the temperature gauge climb into the red zone. I panicked and immediately turned off the AC, switching to full-blast heat to cool it down. Later, the mechanic explained that the AC compressor increases engine load, overworking the cooling system. Common causes include a non-functioning radiator fan, a radiator clogged with poplar fluff, a stuck thermostat that won’t open, or degraded coolant. If this happens, pull over safely, but don’t turn off the engine—keep the heat on max to aid cooling. Once the temperature drops, check the coolant reservoir level. The fan is the easiest to diagnose: start the car, turn on the AC, and see if it spins. If not, it’s either a blown fuse or a faulty temperature switch.
