Hello guys, hopfully i could get some answers, my original radiator blew last week on my 1997 honda civic, i bought a new aluminum one and also replaced my water pump since i noticed it was leaking alittle. I also replaced timing belt since i had to brake it all down. Car runs great and very cool but on real hot days it loses about an inch of water on top of radiator then temp goes up to half when it is at a dead stop and goes back down when fan kicks on this only happens when i am low on water (about every 4 days). What i noticed is that top of radiator gets real hot and water on top boils. Not sure if my fan is turning on when it needs to or the aluminum radiator is doing more harm than good. I also did a compression test on every cylinder and cooling system and its all good. Any suggestions?

Thanks guys!

 

Maybe the head gasket is toast? Or the valve cover gasket? Check for oil in the spark plug wells... It sounds silly but the more details you know your chances of finding your problems increase. I have a similar problem and i'm trying to figure out what's wrong. My radiator is cracked somewhere and i added some 2+2 stop leak and after that i heard that it can clog up your cooling system.

Later edit: my coolant level gets from max to min in 2 days or 30 miles and i see no sign of leaks...

 

Stop using water and put some 50/50 coolant in there.

Get a cooling system tester and load it up and look for the leak.