I have a 93 Pontiac Grand Am, and when i am idling or driving under 50 mph my car starts to overheat. After i get over 50 it starts to cool down. Whats the problem?
The first thing to check is the operation of the cooling fans. Does it come on as engine temp goes up?
Where are the fans located?
Between the engine and the radiator. It/they will be surrounded by a plastic shroud. Open the hood, start the car, and let it warm up. Watch the temperature gauge so you don’t overheat the engine. When the fan(s) kick in, you’ll hear it/them. Keep your hands away from the fan blades!
OK, the fan does not come on as the temp goes up. Now is there a way to check and see if this is a problem other than the fan itself, ie. electrical?
I think the first thing to do is change the thermostat. On most cars, there’s a separate temp switch that controls the cooling fan that is located in the radiator-- if the thermostat is stuck shut, the overheated coolant isn’t reaching the radiator and the fans won’t turn on.
It still could be something with the fan, but since the T-stat is the most common cause of overheating and they’re cheap, I’d do it first.
I had a similar problem with my van, but the fan functioned most of the time. I found that if I turned on the airconditioner the second fan would run and would solve the temperature problem in the stop & go freeway traffic.
It actually turned out to be two other problems:
- the belt tensioner was going bad, so the alternator was not charging the battery properly (the tensioner finally fell apart in 3 pieces when starting the car one day)
- The battery was at the end of its life and was leaking, thus wasn’t holding a charge.
Thus the fan was undervoltage and had trouble starting.
With the new battery and new belt tensioner, I have had no more difficulty.
Now I just need to get the fan running on a friend’s car. That one has STUMPED me. The fan is fine, the relay is fine, the temperture sensor is fine, the thermostat is fine, the fuses and fuse links are fine. The fan runs if I jump the relay output. It has got to be a control wiring problem back to the computer, or the computer itself.
The temperature sensor for the chevy corsica 1993 is on the engine near the thermost housing. Is there a second one in the radiator? The book doesn’t mention it. Even if it did, wouldn’t the computer still start the fan if it was called for by one sensor?