GM Service Manual Online
For 1990-2009 cars only

An engine will overheat if the radiator has any of the following conditions:

    • Leaks
    • Dirt or obstructions in the core

Use a soft bristle brush and clean hot water or a mild detergent solution in order to clean the outside of the radiator core. A car wash or dishwashing liquid is a suitable detergent.

A common city water hose may also be used in order to clean the outside of the radiator. Remove the nozzle from the hose prior to use in order to prevent damage to the fins.

Use one of the following solutions in order to pressure flush and clean the inside of the core tubes:

    • Clean hot water
    • Mild car wash
    • Dishwashing liquid

Use the following steps in order to test the radiator for restrictions:

  1. Warm the engine.
  2. Turn off the engine.
  3. Feel the radiator.
  4. The radiator should be hot along the left side and warm along the right side. There should be an even temperature rise from right to left.

    Cold spots in the radiator indicate clogged sections. Refer to Cooling System Description and Operation for a radiator diagram.