Engine Exhaust Leaking Into Coolant

1. Drain only enough coolant so that the level is just above the top of the cylinder head. Refer to Draining and Filling Cooling System.

2. Disconnect the radiator inlet (upper) hose.

3. Remove the coolant thermostat. Refer to Thermostat Replacement (2.2L) or Thermostat Replacement (4.3L).

Notice: Allowing the drive belt tensioner to snap into the free position may result in damage to the tensioner.

4. Remove the accessory drive belt. Refer to Drive Belt Replacement.

5. Start the engine. Increase the engine speed (RPM) several times, while observing the coolant level. Any noticeable rise in the coolant level or the appearance of bubbles may show that exhaust gas is leaking into the cooling system.

6. If bubbles are present or the coolant level rises noticeably, replace the head gasket. Refer to Head Gasket Replacement.