Exhaust Leaks Into Cooling System

To check for exhaust leaking into the cooling system, drain the system until the coolant level stands just above the top of the cylinder heads, then disconnect the radiator inlet hose and remove the thermostat and fan belt. Start the engine and accelerate several times. At the same time, note any appreciable coolant rise or the appearance of bubbles which may indicate that exhaust gases are leaking into the cooling system.

CAUTION: A worn head gasket may allow exhaust gases to leak Into the cooling system. This can damage the cooling system as the gases combine with the water to form acids which are harmful to the radiator and engine.