2003 Honda Civic overheating

I have a Civic that is overheating after even short drives (ca. 30 mins). Today the heat gauge went up to 3/4 after 20 minutes, and was still rising when I stopped. The radiator fluid is topped up, oil was just changed and is full and not cloudy. No white smoke has been seen out of the tailpipe. The following repairs have already been attempted. New thermostat (replaced 2X), new radiator, timing kit, coolant temp sensors (both), water pump, AC condenser, AC refrigerant. It is still overheating after all that. Why?

Are you sure that the radiator’s electric cooling fans are operating properly?

Are the cooling fans running?

Has anyone checked for a head gasket leak? If exhaust gas is escaping through the head gasket into the cooling system, that will cause an overheat. Have someone do a chemical test on the coolant for acidity which would be caused by the presence of exhaust gases.

When the engine is cold, remove the radiator cap and start the engine.

While the engine idles observe the coolant in the radiator.

If bubbles begin to appear in the coolant while the engine is idling, that’s an indication of a breached head gasket.


Same symptoms with my’03 Civic EX and it was a blown head gasket. 150,000 miles.

This is a classic sign of a breached head gasket. This vintage of Civics is known for that. My duaghter in laws car, same year, same symptoms, same problem. This engine is robust and with a new head gasket will give you many more miles of service.

And by the way, absence of white smoke is not proof the head gasket isn’t leaking.