I have a 1999 cadillac deville. My cooling fan is not turning on. My car is over heating. Is there a connection?
There is nothing really in the water-related part of the system that has anything to do with the fan. The hoses, thermostat, heater core, etc. are simply a conduit to move the water through the engine to provide cooling. The fan is the crucial element to avoiding overheating. While the car is in motion, air flows through the radiator, cooling the coolant down and removing the excess heat. Once you stop, however, or get in a stop-and-go environment, there is limited airflow through the radiator to provide this heat reduction. That is where the fan comes into play. What makes the fan work depends upon what you are asking the vehicle to do. Testing the fan circuitry is rather simple if you understand a few things. The fan only needs to run to cool the engine if the engine coolant gets above a certain temperature (usually about 220F). The fan will be ordered on and run until the coolant drops to about 180-190 (thermostat temp). The confusion is that the thermostat has something to do with turning the fan on. The thermostat only controls the flow of water through the system. It stays closed until the water temp reaches it setpoint (usually 180-190F), then open to allow water to flow through the engine. There is a coolant temperature sensor, usually installed near the point where the thermostat is, and it sends coolant temperature information to the ECM. The ECM uses this information to control fuel-air mixture and to control the cooling fan to operate when needed. The fan and the fan relay can be tested very easily by simply turning on the car's A/C. Even if your A/C unit isn't working, simply putting the dash controls to an A/C position, will automatically power up the cooling fans, since the A/C requires CONSTANT airflow thru the font of the engine to maintain cooling. If the fans don't work in the A/C position, then the problem is not likely to be the coolant temperature sensor. It is more likely to be a fan relay or the fan itself.
Oct 21, 2016 |
1999 Cadillac DeVille