Exhaust Leaks and Noise
Exhaust Leaks1. 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.
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.
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.
Noise
Cooling system noise can be caused by restrictions to coolant flow. This can cause the coolant to boil at some localized point. Symptoms usually appear after extended idling or driving.
1. Possible symptoms are:
^ The engine may make snapping or cracking noises.
^ The radiator hoses may expand or collapse.
^ The coolant heater hoses may vibrate or thump.
^ The coolant heater core may gurgle or surge.
^ The engine overheat lamp may or may not be illuminated.
2. Backflush the cooling system, then retest. Refer to Flushing.
3. Use a mechanic's stethoscope to determine what areas are still affected.
4. Disassemble suspect components for further inspection and cleaning, as necessary.
5. Refer to Cooling System Diagnostic System Check (Cooling System Testing) in order to locate restrictions in the cooling system.