Engine Cooling problem
1998 Honda Civic 4 cyl Two Wheel Drive Automatic 97000 miles
The radiator, radiator temperature cooling switch, and thermostat have been replaced. The coolant is new, and the engine oil doesn't have any water/coolant mixed in it. The radiator fan comes on, and cycles on and off when the engine is up to temperature. I'm assuming the water pump is okay also? There are no leaks I can see and and the coolant level is full in both the radiator and the reserve coolant tank. The coolant is 50% Prestone antifreeze and 50% water.
The problem is that the temperature still rises up close to the red line after about 15 minutes of driving in hot Tucson, Az summer weather. When the temperature starts to rise, we turn the air conditioner off and turn the heater on, then the temperature goes back to normal.
I haven't replaced/tested the coolant temperature sensor which provides an input to the PCU (powertrain control unit), as well as the dashboard temperature gauge. How can I know if the sensor is working properly thruout the temperature range?
Also, the service manual wiring diagrams show an output from the PCU that is wired in parallel with the radiator temperature cooling switch. Is this PCU output supposed to turn the radiator fan on after the car is turned and and the coolant temperature is still above a certain temperature? If so, how long is the radiator fan supposed to run after the car is turned off?
Friday, August 7th, 2009 AT 10:42 PM