1997 ex accord, we have had the hose from the radiator replaced, ran block sealer, and also took it to a radiator shop to test for leaks--no leaks. It does well in the morning but mid-day when it is 100 degrees and I have to stop at a light it creeps up to hot, but if I hit the increase the engine up to 1.5 rpms then the car indicator on the inside cools down below half. I noticed that when the air compressor comes on it does not want to idle right could this be a problem. Does any one know why it could still be getting hot...??? Thanks for any help....

 

1st thing: When it gets hot, open the hood and see if the fans are running.

If they are, it could be air in your coolant system. You mentioned that it cooled down if you raised the RPM. That increases the amount of coolant the pump moves and can overcome the air block. Could also be the pump itself going bad.

 

add coolant to the radiator and or the reservior tank. i had a problem like that too. my temp gauge will rise in im stopped but it would lower if im driving. don't forget to mix water with the coolant or else it would still overheat.