I have a 1994 4-cylinder 2.2L Chevy Corsica with approximately 146,000 miles on it. While doing some short-distance (18 miles) highway driving, my battery light came on and I saw that the temp gauge was high. So, I quickly pulled off and into a gas station. Don't know how I made it, as there was coolant all over my drive belt; which was completely off. The coolant was only in the area of the drive belt, so I left the hood up to let it all dry out. I inspected all the hoses and found no signs of wear. Started the engine and no leaks. Haven't moved the car, but let the engine get up to temp, to see if it was the pump or the thermostat. The pump is definately working and so is the thermostat. I noticed that the fan never turned on after 20 minutes of operation and shut the engine off. Still no leaks, at this point. I removed the radiator fan and jumpered it directly to the battery - started right up. I am using the Haynes Repair Manual; which indicates that if the fan motor tests OK, the fault lies in the coolant temperature switch, the relay, or the wiring which connects the components. While, I realilze that it would be extremely difficult to include a wire-routing diagram in such a manual, it would have been nice to see the location of the coolant temperature switch and relay. Can you tell me where they are located and if I have correctly diagnosed the problem. As for the spraying of the coolant - I figured that the vent cap on the reservoir couldn't keep up with the boiling-hot coolant and it vented out the water pump gasket. As my wife followed me home, she told me that leakage was intermittant; which led me to beleive that the thermostat was operational. Thank you for you time.
I think you are right and the thermostat is good, I believe the fan is not coming on due to a fautly coolant temperature switch and this is why the car overheated. I don't have a wiring diagram but I do know that the coolant switch is located in the thermostat housing. Wish I could of been more helpful Good luck