GM Service Manual Online
For 1990-2009 cars only

Important: Review the system operation in order to familiarize yourself with the system functions.

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the Cooling System. Refer to Checking Aftermarket Accessories in Wiring Systems.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
    • Inspect the engine coolant recovery reservoir for the proper coolant level.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  HOT COOLANT TEMP Message Always On
    •  HOT COOLANT TEMP Message Inoperative
    •  LOW COOLANT Message Always On
    •  LOW COOLANT Message Inoperative
    •  Engine Overheating
    •  Loss of Coolant
    •  Thermostat Diagnosis
    •  Engine Fails To Reach Normal Operating Temperature
    •  Coolant Concentration Testing
    •  Cooling System Leak Testing
    •  Pressure Cap Testing