calteg

I have a 99 civic LX that recently began overheating. It drives fine for roughly 20 minutes, then the temp gauge starts climbing and eventually maxes out. Happens both idling and at speed, though it cools down very slightly at speed.

The strange part is that the A/C seems to be tied to the overheating. A/C works fine for the first 20 minutes or so, as the car overheats, the A/C begins cutting on and off. It'll work fine for 3 or 4 minutes, then blow hot air.

I'm going to swap out the thermostat and bleed the system, any other suggestions?

axis11

First verify that the radiator fan is turning on.

Ryan Lwin

Caps. Check for them or replace them. They are cheap.

Cody Pereira

thermostat sticking? Im coming from the American muscle world and I know that when the thermostat sticks and doesn't open up when the motor gets to temperature it will cause the motor to overheat. Check it out, its a cheap fix too!

calteg

Thermostat has been swapped, system was burped properly, verified that both fans come on when they're supposed to. Also did a head gasket test, no exhaust gas is leaking into the cooling system...kinda stumped.

Temp seems to be okay as long as I'm at speed. A/C on or idle too long and it starts to overheat. The odd thing was, after I burped the system, it ran fine for 2 days, then started acting up again. Ideas?

Former User

NEVER let your engine overheat to this level. If it hasn't happened already, you will destroy your engine.

Does the radiator fan run when the engine gets hot?

Is the lower radiator hose much cooler than the upper one when the engine gets hot?