Ok, I have a 93 Civic with an H22A swap. The problem is when I am stopped at a light or in traffic the engine starts to run hot. Temp gauge goes about 3/4 of the way up but not all the way to the red, when I start moving the temp will drop back down to normal operating temp. I thought it was the fan not operating but I have checked and it seems to be functioning just fine, then checked coolant level and it is fine, doesnt seem to be any visible blockage on the radiator. Oil doesnt show sign of a bad headgasket but I know it doesnt always show up in the oil. Any ideas of what could be causing this to happen?

 

I know you said the fans work, I would verify that they turn on. While the engine is idling, watch the temp gauge. The fans should turn on before the gauge rises above half. Watch the temp between the upper and lower radiator hoses, there shouldn't be a big difference between the hoses. A sticking thermostat, bad water pump, plugged radiator can cause the engine to overheat. If everything is ok, the temp switch could be bad. A blown head gasket or crack in the head or block, does not mean it will show up in the oil. Was the cooling system upgraded with the engine swap?

 

Yeah the fan operates when idling but it could be turning on at the wrong time, hoses are roughly the same temp. and i know the signs dont always show in the oil. the system wasnt upgraded but i havent had a problem out of it since i owned the car. I will be upgrading it though in a few weeks, just need to make sure i get whats wrong right now fixed

 

Test your coolant too see if u have a blown head gasket. They sell this one thing that changes color to blue if exaust gasses are going to your cooling system. It works. Try bleeding cooling system one more time

 

Well, i got tricked, lol. My fan isnt working properly all the time, everytime i checked i yesterday it happened to be working but wasnt when i check earlier. lol.

 

There should be a coolant temp switch in the radiator, if its not working correctly, it could turn the fans on at too high of a temp, or not at all. The thermostat could be sticking or just partially opening. The tool that hondaguy mentions is a combustion leak detector. The combustion leak detector kit tests for exhaust gasses in the cooling system, they cost $25 to $50 depending on which kit you buy. I would replace the thermostat first, especially if its old or has a lot of miles on it.