Cooling System Troubleshooting Chart

Fig 1: Cooling System Troubleshooting Chart (1 Of 2)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Cooling System Troubleshooting Chart (2 Of 2)

Courtesy of GENERAL MOTORS CORP.

NOTE: During extremely cold weather, 10°F (-12°C) or colder, the engine's coolant temperature will decrease quickly when idling with the heater fan on high speed. Cool air may flow from the heater outlets. The fan control switch should be set at a slower speed position (fan speed I or II) to maintain the hottest air flow.

NOTE: The thermostat's rubber seat on the main poppet valve will deteriorate if it is contacted by oil. If the rubber seat is found soft, or cracked:

• Determine the cause for oil in cooling system.
• Flush cooling system as following the instructions in the cooling section of the manual.
• Replace thermostat cartridge.
• Fill cooling system with a 50/50 solution of Dex-Cool™ antifreeze and clean water.