I compare overheating at 55MPH to jogging with a sock in your mouth. Usually the radiator fan is closer to the middle of the radiator. Some cars will have two electric fans, one is for the radiator and the other is the air conditioner condenser fan. Removing the radiator from the vehicle for disassembly and cleaning or radiator replacement are the only two real cures for a clogged radiator.If your vehicle does not have an electric cooling fan on the radiator it will have a belt driven fan blade and fan clutch.If there is a restriction in the system like a kinked radiator hose, a restricted radiator, or a stuck thermostat, it will produce the same affect as the sock in the mouth scenario.The air conditioning compressor will require the cooling fan to operate at idle as long as the compressor is on.
Most cars and trucks will hold 1 1/2-2 gallons of coolant and water mixture.What if the engine overheats while at high speeds on the freeway?Again, airflow and coolant circulation are crucial.Using a can of “radiator flush” additive might help as preventive maintenance, but will probably just be a waste of time and money trying to correct a restricted radiator.First: Is there enough coolant/antifreeze in the radiator? Don’t just look inside the plastic overflow bottle, but remove the radiator cap (when the engine is cold) and look inside the radiator. A quick way to check the cooling fan operation is to turn on the air conditioner. Rust and water calcification can accumulate in the radiator and drastically reduce the flow of coolant at high speeds. The radiator is the primary heat exchange for the engine, and airflow is crucial. If you see any obvious fluid loss on the ground or in the engine compartment, you should also have the system tested for leaks. You should be able to physically see the fluid level if it is at its proper level. The function of the cooling fan is to improve airflow across the radiator at stops and low speeds. At 55MPH the water pump is pumping a large amount of hot antifreeze throughout the cooling system.
What you want to determine with either fan situation is that there is ample airflow across the radiator at idle. If you have to add more than a pint of fluid you should have the cooling system pressure tested for a leak. The fan is controlled by sensors that regulate the engine temperature and additional load that might be placed on the engine.Second: If no coolant leak or low fluid level is present, then determine when the overheating complaint occurs. This fan should be pulling a large amount of warm to hot air across the radiator onto the engine.If the engine overheats while at a stop or idle only:Most front wheel drive cars use an electric cooling fan motor located in front or behind the radiator. The faster and longer you jog, the more air you are going to require, and with a sock in your mouth you disposer Factory are going to have to breath extra hard to maintain the proper amount of air to keep you going. The radiator fan is responsible for engine cooling, and the condenser fan is responsible for increasing air conditioning efficiency at idle and low speed. The cooling fan should come on with the air conditioner compressor.
To properly diagnose your overheating complaint we need rule out a few basic things. At 55 MPH we can assume you have ample airflow across the radiator, so proper antifreeze circulation is the thing to inspect.