My usually reliable 1994 Accord Wagon is driving me crazy. It has suddenly started overheating. The radiator and water pump have about 5000 miles on them before it started overheating. I replaced the thermostat, the radiator cap and the hoses. Didn't solve anything. No water vapor in exhaust. No water in the oil so a head gasket is probably not the issue. My fan is working. Car idles at about 2500 when it starts getting hot. Only overboiled once but haven't left the confines of the neighborhood to keep from being stranded. What next?? Didn't I just replace the entire cooling system???

 

Compression test to see if the head is warped.

 

Compression is very solid. Only has 140,000 miles. Turns out that the overheating after replacing the thermostat and cap must have been air pockets. Pulled the thermostat and drilled two 1/8" holes in the flange to purge air. Filled radiator with engine running and problem appears to be solved.