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.
November, 20, 2007 AT 10:42 PM
What damage has the pump sustained? Is it leaking? Will it turn? There are a few ways to determine a head gasket issue, There are chemical tests to determine combustion gasses in the coolant, white smoke, rusty coloured spark plugs, constant bubbles in the cooling system, 2 low compressions if the gasket has burnt the fire ring between two cylinders. Water in the oil, water in a cyl after a coolant pressure test. I will depend on where the problem lies, head gasket, cracked head and how sever the problem is, but it is always preferable to have the engine at operating temp to help with a diagnosis.