The following explains your cooling system and how to add coolant when it is low. If you have a problem with engine overheating, see Engine Overheating .
A 50/50 mixture of clean, drinkable water and proper coolant will:
| • | Give freezing protection down to -34°F (-37°C). |
| • | Give boiling protection up to 265°F (129°C). |
| • | Protect against rust and corrosion. |
| • | Help keep the proper engine temperature. |
| • | Let the warning lights and gages work as they should. |
What to Use
Use a 50/50 mixture of clean, drinkable water and coolant that meets GM Specification 1825M, which will not damage aluminum parts. You can also use a recycled coolant conforming to GM Specification 1825M with a complete coolant flush and refill. If you use this coolant mixture, you do not need to add anything else.
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 the proper coolant.
Notice: If an improper coolant mixture is used, the engine could overheat and be badly damaged. The repair cost would not be covered by the vehicle warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core, and other parts.
If you have to add coolant more than four times a year, have your dealer check your cooling system.
Notice: If you use the proper coolant, you do not have to add extra inhibitors or additives which claim to improve the system. These can be harmful.
Checking Coolant
The engine coolant surge tank is located in the rear of the engine compartment. See Engine Compartment Overview for more information on location.
Caution: Turning the surge tank pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn you badly. Never turn the surge tank pressure cap -- even a little -- when the engine and radiator are hot.
The vehicle must be on a level surface. When your engine is cold, the coolant level should be between the MAX (Maximum) and MIN (Minimum) marks on the coolant surge tank. The level rises at engine operation temperature and drops again when the engine cools down.
Adding Coolant
If the level falls below the MIN mark, add the proper coolant mixture at the surge tank, but only when the engine is cool. If the surge tank is empty, a special fill procedure is necessary. See Cooling System for instructions on "How to Add Coolant to the Coolant Surge Tank."
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 replacing the pressure cap, make sure it is hand-tight and fully seated.
