When you decide it is safe to lift the hood, here is what you will see:
3.6L V6 shown, 4.6L V8 similar
Electric Engine Cooling Fans
Coolant Surge Tank and Pressure Cap
Some vehicles may be equipped with an engine driven fan, as well as the electric pusher fans (A) which are located behind the vehicle's grille.
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 surge tank is boiling, do not do anything else until it cools down. The vehicle should be parked on a level surface.
When the engine is cold, the coolant level should be at or slightly above the FULL COLD/FROID line on the side of the coolant surge tank. 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 fans are running. If the engine is overheating, both fans should be running. If they are not, your vehicle needs service.
Notice: Engine damage from running your engine without coolant is not covered by your warranty. See Overheated Engine Protection Operating Mode 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 Surge Tank
If you have not found a problem yet, check to see if coolant is visible in the surge tank. If coolant is visible but the coolant level is not at the FULL COLD/FROID line on the side of the coolant surge tank, add a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant at the coolant surge tank, but be sure the cooling system, including the coolant surge tank pressure cap, is cool before you do it. See Engine Coolant for more information.
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 coolant surge tank pressure cap -- even a little -- they can come out at high speed. Never turn the cap when the cooling system, including the coolant surge tank pressure cap, is hot. Wait for the cooling system and coolant surge tank pressure cap to cool if you ever have to turn the pressure cap.
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.
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.
If no coolant is visible in the surge tank, add coolant as follows:
- You can remove the coolant surge tank pressure cap when the cooling system, including the coolant surge tank pressure cap and upper radiator hose, is no longer hot. Turn the pressure cap slowly counterclockwise (left) about one-quarter turn and then stop.
- Then keep turning the pressure cap slowly, and remove it.
- Fill the coolant surge tank with the proper mixture, to slightly above the FULL COLD/FROID line on the side of the coolant surge tank.
- With the coolant surge tank pressure cap off, start the engine and let it run until you can feel the upper radiator hose getting hot. The upper radiator hose is the largest of the hoses which comes out of the radiator, on the passenger's side of the vehicle. Watch out for the engine cooling fans.
- Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated.
If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left.
By this time, the coolant level inside the coolant surge tank may be lower. If the level is lower, add more of the proper mixture to the coolant surge tank until the level reaches the FULL COLD/FROID line on the side of the coolant surge tank.
Start the engine and allow it to warm up. If the Check Coolant Level message does not appear on the Driver Information Center, the coolant is at the proper fill level. If a Check Coolant Level message does appear, repeat Steps 1 to 3 then reinstall the pressure cap, or see your GM dealer.
