Here's the scoop: My car is overheating when it's at stand still. When it is in motion, it cools back down. Is suspect the fan isn't working, but I'm not sure. Any ideas on what the problem might be?
Is it leaking? Check your fan and also your water pump. As long as the radiator seems okay its likely one of those two things.
I had the same problem, it would overheat at lights, stop signs and even speed breakers. I would have to put the car in neutral and keep it revved up... Turned out to be that the headgasket was blown and it was leaking engine oil into the radiator... Check your coolant reservoir...
A water pump would still have the car overheating if it was moving. It's a fan. My Land Rover had the same problem, and it was two little fans that had gone out. Mine was fairly pricey, also. Both fans were $300 a pop.
Check your thermostat as well. Might have screwed up and is now permanently closed (i.e. coolant not circulating anymore).
You can't test it without taking it to a mechanic but that is usually a main cause of something like this, especially saying it cools when you drive. The air and fan help keep the car cooled but once you stop, if the water pump isn't working it'll heat up fast. Take it to a mechanic and ask him to check your water pump. You can check the fan by turning on the A/C I believe. Ah yes, have someone check the thermostat as well. Sometimes the water pumps leak, but its one of those two or three things for sure. Been there my man.
Not everything requires a mechanic. If I can check a thermostat, any man on this board sure as hell should be able to! OOOOOOHHHHH
Remove your radiator cap (when it is cool), then start your engine. When your engine warms up to operating temperature your thermostat should open and if your water pump is working you will see water move across the top of your radiator. The thermostat acts like a valve the lets the water flow when the engine needs to be cooler and closes when the engine needs to be warmer. If you have an electric fan, you simply observe it and see if it is turning. If your fan is turned by a belt on the engine, just because it is turning does not mean all is well. There will also be a fan clutch that can fail. The fan will turn but it does not turn fast enough to cool the radiator. This is not simple to diagnose. I know how, but I can't think of a way to tell you that won't get you hurt.
also check your oil level. We had an old car that would run low on oil and start over heating just like you are descibing. Add oil and the problem went away until it got low on oil the next time.
It sounds like you have a mechanical fan clutch, and it's going out. When it is at a standstill, the clutch is not adequately hold the fan enough to provide air...more than likely, the fan is free spinning much slower than the speed it is meant to be operated at. Once you are in motion, the incoming air takes care of the cooling. It might also just need water. Mechanical (belt driven) water pumps go out when the bearing give and the water "bleeds" out. Busted thermostats typically do not "cycle". The get stuck open or closed.
What kind of compression were you running to blow the head gasket? It may have heated up before causing the heat to warp the head enough to blow out the head gasket. Typically, these things don't blow except for in extreme conditions such as high compression or overheated temperatures.
