98 Honda CRV, Overheating randomly what is the cause?

Hi, I have a 1998 Honda CRV that tends to overheat randomly (after an hour or so of driving) and go back down to normal. I replaced the thermostat and the problem still persists. We also checked the water levels and it does not seem to loose any water. What could be the cause?

Hi in most cases the radiator cap has lost it's capability as the spring in the cap has become weakened over time. So a replacement cap is required.

The engine being almost 30 years old it might be the head getting too hot then distorting thus leaking coolant pressure.

Run the motor for 20 minutes with the radiator cap removed from the radiator. Have the climate controls set to the hottest setting with the blower fan turned off. Add a 50/50 mix of antifreeze and water to the radiator as the air purges from the cooling system. If the air keeps coming out and won't go away you need to have a "block test' done to see if the head gasket is bad.