I have a honda civic 2000 and recently I noticed that it overheat only after exiting a long drive on highway. The car does not overheat for my normal daily commutes (within the city).
I tried the following:
- Checked coolant on bot radiator and overflow tank.
- Changed the thermostat
- No leak on the ground in the garage where I parked the car overnight
- No noise to lead to an eventual issue with water pump
- Radiator fan is kicking ok
- Had a mechanic do the chemical test for the head gasket: negatif
- Found that there is air in the cooling system:
tried to burp the system 2 times but air is still in the coolant system. Not sure where its coming from !!?? Might be that this could be causing the overheating ?
- Found a crack on the manifold and changed the manifold then tried to get rid of the air (burping the system): no success. The air is still not removed completely.
- Changed the radiator cap.
What can I do next to diagnose the overheating condition that happens only after exiting long drive highway ?
p.s: I took the car to 2 different mechanic. They spent 30 minutes to find out the cause(s) and could not figure out what is wrong.