1985 Pontiac Firebird

Engine Cooling problem
1985 Pontiac Firebird V8 Two Wheel Drive Manual 30 miles

I have a new radiator and thermostat but the engine continues to try n overheat. Could this possible be cause by a bad radiator cap?I would really like to find out the problem as I have recently put a new engine in the car as well as the rest of the parts being new.
March 12, 2008.

Did you bleed the cooling system? If so see below

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.

Mar 16, 2008.