My 1996 Integra GS-R has been overheating pretty badly lately, I changed the thermostat and tried it without one and it continued to overheat. The electric fans are functioning properly and whenever I've changed the coolant there is no rust or muck in the radiator. The water pump is working, when I pull the throttle it seems to be pulling the water through just fine. The heater only blows hot air about half the time which looks like there would be clogs in the system, but the lack of rust/muck is boggling, has anyone ever heard of anything else causing these odd problems?

 

Have you fully bled the coolant system everytime it has been refilled? Are you 100% sure the water pump is working?

 

Just because there is nothing in the radiator doesn't mean there isn't an obstruction inside the block (I had the same problem with my S13). You need to do a leak down check on the cooling system and I'd get your compression tested too. If everything else is working, you could have a head gasket issue.

 

of course you had that problem with your s13, its an s13.

I agree though, get a compression test and maybe get someone to presure test your coolant system (just need a pressure gauge hooked up to rad cap) I wouldn't eliminate your radiator unless you really know it is clean and in good shape.

 

Yeah, I'll just have to take it in and get the system cleared out