GM Service Manual Online
For 1990-2009 cars only

When you decide it is safe to lift the hood, here is what you will see:


Object Number: 1454856  Size: G1
  1. Electric Engine Cooling Fan

  2. Engine Coolant Recovery Tank

  3. Radiator Pressure Cap

Caution: An electric engine cooling fan under the hood can start up even when the engine is not running and can cause injury. Keep hands, clothing, and tools away from any underhood electric fan.

If the coolant inside the coolant recovery tank is boiling, do not do anything else until it cools down. The vehicle should be parked on a level surface.

The coolant level should be at or above the FULL mark. If it is not, you may have a leak at the pressure cap or in the radiator hoses, heater hoses, radiator, water pump, or somewhere else in the cooling system.

Caution: Heater and radiator hoses, and other engine parts, can be very hot. Do not touch them. If you do, you can be burned.

Do not run the engine if there is a leak. If you run the engine, it could lose all coolant. That could cause an engine fire, and you could be burned. Get any leak fixed before you drive the vehicle.

If there seems to be no leak, with the engine on, check to see if the electric engine cooling fan is running. If the engine is overheating, the fan should be running. If it is not, your vehicle needs service.

Notice: Engine damage from running the engine without coolant is not covered by the warranty.

How to Add Coolant to the Coolant Recovery Tank

If you have not found a problem yet, but the coolant level is not at or above the FULL mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant at the coolant recovery tank. See Engine Coolant for more information about the proper coolant mixture.

Caution: Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid such as alcohol, can boil before the proper coolant mixture will. Your vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot but you would not get the overheat warning. Your engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and a proper coolant.

Notice: In cold weather, water can freeze and crack the engine, radiator, heater core and other parts. Use the recommended coolant and the proper coolant mixture.

Caution: You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts are hot enough. Do not spill coolant on a hot engine.

When the coolant in the coolant recovery tank is at the FULL mark, start your vehicle.

If the overheat warning continues, there is one more thing you can try. You can add the proper coolant mixture directly to the radiator but be sure the cooling system is cool before you do it.

Caution: Steam and scalding liquids from a hot cooling system can blow out and burn you badly. They are under pressure, and if you turn the surge tank pressure cap -- even a little -- they can come out at high speed. Never turn the cap when the cooling system, including the surge tank pressure cap, is hot. Wait for the cooling system and surge tank pressure cap to cool if you ever have to turn the pressure cap.

How to Add Coolant to the Radiator


Object Number: 1454857  Size: B3
  1. You can remove the radiator pressure cap when the cooling system, including the radiator pressure cap and upper radiator hose, is no longer hot. Turn the pressure cap slowly counterclockwise until it first stops. Do not press down while turning the pressure cap.
  2. If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left.

  3. Then keep turning the pressure cap, but now push down as you turn it. Remove the pressure cap.

  4. Object Number: 1454858  Size: B3
  5. Fill the radiator with the proper coolant mixture, up to the base of the filler neck. See Engine Coolant for more information about the proper coolant mixture.

  6. Object Number: 1454859  Size: B3
  7. Then fill the coolant recovery tank to the FULL mark.
  8. Put the cap back on the coolant recovery tank, but leave the radiator pressure cap off.

  9. Object Number: 1454861  Size: B3
  10. Start the engine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine cooling fan.
  11. By this time, the coolant level inside the radiator filler neck may be lower. If the level is lower, add more of the proper coolant mixture through the filler neck until the level reaches the base of the filler neck.
  12. Then replace the pressure cap. At any time during this procedure if coolant begins to flow out of the filler neck, reinstall the pressure cap. Be sure the ears on the pressure cap are in line with the vent tube.