Initial Inspection and Diagnostic Overview

1. Verify the customer concern by operating the vehicle.
2. Visually inspect the following components of the engine cooling system.

Mechanical
^ Damaged hoses or loose/damaged hose clamps.
^ Damaged water thermostat.
^ Damaged cylinder head gaskets.
^ Damaged intake manifold gasket.
^ Damaged water pump.
^ Damaged radiator or heater core.
^ Damaged degas bottle.
^ Coolant level and condition.
^ Fan blade condition and mounting.

Electrical
^ Open fuse.
^ Damage to wiring harness.
^ Corroded connections.
^ Circuitry open/shorted.
^ Damaged constant control relay module.
^ Damaged engine cooling fan motor, fan blade and fan shroud assembly.

3. Look for obvious shorts, opens, or damage in the wiring harness for the engine cooling fan motor.
4. Check the water thermostat for proper spring tension. Also check the water thermostat to make sure that there is not a large gap between the valve plate and the thermostat housing.
5. If fault is not visually evident, proceed to Diagnosis By Symptom.
Symptom Related Diagnostic Procedures