GM Service Manual Online
For 1990-2009 cars only

When it is safe to lift the hood, this is what will be seen:


Object Number: 1366907  Size: B3
  1. Coolant Recovery Tank

  2. Electric Cooling Fan

  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.


Object Number: 809769  Size: A3

When the engine is cold, the coolant level should be at or above the COLD mark on the coolant recovery tank.

If it is not , there may be 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 fans are running. If the engine is overheating, both fans should be running. If they are not, the vehicle needs service.

Notice: Engine damage from running your engine without coolant is not covered by your warranty. See "Overheated Engine Protection Operating Mode" in the Index for information on driving to a safe place in an emergency.

Notice: Using coolant other than DEX-COOL® can cause premature engine, heater core, or radiator corrosion. In addition, the engine coolant could require changing sooner, at 30,000 miles (50 000 km) or 24 months, whichever occurs first. Any repairs would not be covered by the vehicle warranty. Always use DEX-COOL® (silicate-free) coolant in the vehicle.

How to Add Coolant to the Coolant Recovery Tank

If no problem has been found yet, but the coolant level is not at the COLD mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL® engine coolant at the coolant recovery tank. See Engine Coolant for more information.

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


Object Number: 809779  Size: B3

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 COLD mark, start the vehicle.

If the overheated warnings continue, there is one more thing that can be done. Add the proper coolant mixture directly to the radiator, but be sure the cooling system is cool before this is done.

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.


Object Number: 810983  Size: B3

How to Add Coolant to the Radiator

Notice: Your engine has a specific radiator fill procedure. Failure to follow this procedure could cause your engine to overheat and be severely damaged.

Turn the pressure cap slowly counterclockwise until the first stop. Do not press down while turning the pressure cap.


    Object Number: 1334877  Size: B3
  1. The radiator pressure cap can be removed when the cooling system, including the radiator pressure cap and upper radiator hose, is no longer hot.
  2. If a hiss is heard, 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. 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.

  5. Remove the 3800 Series II V6 engine cover shield to access the bleed valve.

  6. Object Number: 856178  Size: B3
    3.1. Clean the area around the engine oil fill tube and cap before removing. Twist the oil fill tube, with cap attached, counterclockwise and remove it.

    Object Number: 809767  Size: B3
    3.2. If the vehicle has a supercharged engine, remove the nut in the center of the cover shield.
    3.3. Lift the engine cover shield at the front, slide the catch tab out of the engine bracket and remove the cover shield.
    3.4. Put the oil fill tube, with cap attached, in the valve cover oil fill hole until you are ready to replace the cover shield.

    Object Number: 809230  Size: A2

    After the engine cools, open the coolant air bleed valve. The bleed valve is located on the thermostat housing.


    Object Number: 809780  Size: A3

    Fill the radiator with the proper DEX-COOL® coolant mixture, up to the base of the filler neck. See Engine Coolant for more information about the proper coolant mixture.

  7. If a stream of coolant is coming from an air bleed valve, close the valve. Otherwise, close the valve after the radiator is filled.
  8. Rinse or wipe any spilled coolant from the engine and the compartment.
  9. Replace the 3800 Series II V6 engine cover shield.
  10. 7.1. Remove the oil fill tube, with cap attached, from the valve cover.
    7.2. Insert the catch tab on the cover shield under the bracket on the engine.
    7.3. Place the hole in the cover shield over the hole in the valve cover. Install oil fill tube and cap by twisting clockwise.
    7.4. If the vehicle has a supercharged engine, install the nut in the center of the cover shield.

    Object Number: 809779  Size: B3
  11. Then fill the coolant recovery tank to the COLD mark on the coolant recovery tank.
  12. Put the cap back on the coolant recovery tank, but leave the radiator pressure cap off.

  13. Object Number: 809768  Size: B3
  14. Start the engine and let it run until the upper radiator hose feels that it is getting hot. Watch out for the engine cooling fans.
  15. By this time, the coolant level inside the radiator filler neck may be lower. If the level is lower, add more of the proper DEX-COOL® coolant mixture through the filler neck until the level reaches the base of the filler neck.
  16. 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 arrow on the pressure cap lines up like this.
  17. Check the coolant in the recovery tank. The level in the coolant recovery tank should be at the HOT mark when the engine is hot or at the COLD mark when the engine is cold.