Mechanics

OVERHEATING + A/C ISSUE

1994 Pontiac Sunbird

Engine Cooling problem
1994 Pontiac Sunbird 4 cyl Front Wheel Drive Automatic 204000 miles

To start off, my cars heater/ac fuse (25 amp) keeps blowing. Shortly after this happened my car overheated. I opened the hood of the car and noticed that coolant was spitting out of the radiator cap. Seemed to be under alot of pressure. When the car cooled, I pulled the radiator cap for inspection. I found cracks in the seal and assumed that this was the problem. For the overheating anyway. I replaced the radiator cap with a new one, and then replaced a new fuse for the heater/ac. I started the vehicle. With the hood open watch for any leaks, smoke, etc. The ac was working, the engine reached normal operating temp. The fan kicked on and then the temp went down. The ac was still working and everything seemed to be operating normally. I decided to take my car for a cruse. The heater/ac fuse blew, I continued to drive, then my cars engine overheated. So I inspeced the water pump, no leaks from the weep hole, and then inspected the thermostat. The thermostat seemed to be okay, but I replaced it with a new one. Now with the car being replaced with a new thermostat, I put a new heater/ac fuse in, and started the car. With the hood open inspected for leaks, smoke etc. The engine reached normal operating temp. And the fan kicked on. There started to leak a little out of the new radiator cap but then subsided. Then engine now slowly cooling, the fan running, and the ac on, it seemed that the thermostat might have been the problem. I started for a test drive. Everything seemed normal during driving for 30 min, except that the heater/ac fuse blew again, once parked for 5 min. The engine began to overheat, coolant spitting out of the radiator cap, but that is the only leak.I was wondering if the heater/ac fuse blowing would have some kind of connection with the fan operating normally. I suspected that the when fuse blows that it is not sending to the fan therefore the fan is not turning on, and the coolant is not being circulated properly, causing overheating. Could this be?
thankyou
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Dealsbests
August 22, 2010.



Yes, that sounds like exactly what is happening. If the cooling fan is dropping out when the fuse blows, that would explain both the overheating and the A/C problems. I suspect the fan motor overloading the circuit may also be the cause of the fuse blowing.
Be careful here that you don't turn a fan problem into a blow head gasket by overheating it too much.

Wrenchtech
Aug 22, 2010.