My 94 civic standard 4 cyl. is overheating when you drive it over about a 5 mile trip. Engine will not overheat while idling in the garage only when it is driven. When overheating occurs the heater starts blowing cold air so I am thinking it is some kind of circulation problem. Car has new radiator, water pump and thermostat. No oil in the oil or water in the exaust. When car gets hot only water lost is what goes into overflow tank. Am I right in assuming I have a circulation problem? If so why doesnt the engine overheat while idling in the garage and soesnt over heat on short trips less than 5 mile or so. Also while idling I am not getting any pressure in the radiator. Any help? Thanks Russ

 

Sounds to me like its the coolant system is air locked. The rad most likely boiled over one time when it overheated. If it did, when you put coolant in did you have the heater on max defrost to make sure it circulated through heater core? I would suggest "burping" your coolant system (letting the car run with the rad cap off until you see it burp all the air out) and see if that helps the problem.

 

thanks for your post. All the air was burped from the system. One thing the car does right before it starts overheating is the heater stops blowing warm air. Almost immediately the engine runs hot. Another reason I think it may be a circulation problem is the top radiator hose is hot and steam coming from the overflow and the bottom hose is cool. Again I have a new radiator, water pump and thermostat. What would cause water to stop circulating after 2 or 3 miles of driving?