GM Service Manual Online
For 1990-2009 cars only

The cooling system in the vehicle for all engines and the intercooler is filled with DEX-COOL®. This coolant is designed to remain in the vehicle for five years or 150,000 miles (240 000 km), whichever occurs first.

The following explains the cooling system and how to check and add coolant when it is low. If there is a problem with engine overheating, see Engine Overheating.

What to Use

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.

Use a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant. If using this mixture, nothing else needs to be added. This mixture:

    • Gives freezing protection down to -34°F (-37°C), outside temperature.
    • Gives boiling protection up to 265°F (129°C), engine temperature.
    • Protects against rust and corrosion.
    • Will not damage aluminum parts.
    • Helps keep the proper engine temperature.

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.

Notice: If extra inhibitors and/or additives are used in the vehicle's cooling system, the vehicle could be damaged. Use only the proper mixture of the engine coolant listed in this manual for the cooling system. See Recommended Fluids and Lubricants for more information.

Checking Coolant

The vehicle must be on a level surface when checking the coolant level.

The engine coolant reservoir is located in the engine compartment on the driver side of the vehicle. See Engine Compartment Overview.

Check to see if coolant is visible in the surge tank. If the coolant inside the surge tank is boiling, do not do anything else until it cools down. If coolant is visible but the coolant level is not at or above the FULL COLD mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant at the coolant surge tank, but be sure the cooling system is cool before this is done. See Engine Coolant for more information.

If the engine is warm or hot, the coolant level should be at or above the FROID/FULL COLD line on the side of the coolant surge tank. If the engine is cold, the coolant level should be near the FROID/FULL COLD line on the side of the coolant surge tank. If it is not, there could be a leak in the cooling system.

How to Add Coolant to the 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.

Notice: This vehicle has a specific coolant fill procedure. Failure to follow this procedure could cause the engine to overheat and be severely damaged.

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.

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.

If coolant is needed, add the proper DEX-COOL® coolant mixture at the coolant surge tank.

If no coolant is visible in the surge tank, add coolant as follows:

  1. 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 about one-quarter turn and then stop.
  2. If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left.


    Object Number: 829455  Size: B3
  3. Then keep turning the pressure cap slowly and remove it.

  4. Object Number: 829456  Size: B3
  5. Fill the coolant surge tank with the proper mixture, to slightly above the FROID/FULL COLD line on the side of the coolant surge tank.
  6. 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 top hose coming out of the radiator, on the passenger side of the vehicle. Watch out for the engine cooling fans.
  7. 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 FROID/FULL COLD line on the side of the coolant surge tank.

  8. Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated.

Notice: If the pressure cap is not tightly installed, coolant loss and possible engine damage may occur. Be sure the cap is properly and tightly secured.

Recheck the coolant level in the bottle next time you use your vehicle to insure the system is full when cold. See Engine Coolant.

Checking Coolant in the Intercooler System (CTS-V)

The vehicle must be on a level surface when checking the coolant level.

The super charged engine intercooler coolant fill bottle is located in the engine compartment on the passenger side of the vehicle. See Engine Compartment Overview.

Check to see if coolant is visible in the coolant fill bottle. If the coolant inside the coolant fill bottle is boiling, do not do anything else until it cools down. If coolant is visible but the coolant level is not at or above the COLD FILL mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant at the coolant fill bottle, but be sure the cooling system is cool before this is done.

If the engine is warm or hot, the coolant level should be at or above the COLD FILL line on the side of the coolant fill bottle. If the engine is cold, the coolant level should be near the COLD FILL line on the side of the coolant fill bottle. If it is not, you could have a leak in the cooling system.

Adding Coolant to the Intercooler System Coolant (CTS-V)


Object Number: 2022757  Size: B3
  1. Remove the intercooler system pressure cap when the intercooler system hoses are no longer hot. Turn the pressure cap slowly counterclockwise about one-quarter of a turn. If you hear a hiss, wait for that to stop. This allows any pressure still left to be vented.
  2. Then keep turning the pressure cap slowly and remove it.
  3. Add the proper DEX-COOL® coolant mixture to the fill neck until the coolant reaches the COLD FILL line on the fill neck.
  4. With the intercooler system pressure cap off, start the engine and let it run for a couple of minutes. Then turn the engine off. By this time, the coolant level inside the fill neck may be lower. If the level drops to where coolant is no longer visible in the horizontal tube section of the fill neck, with the engine off add more of the DEX-COOL® coolant mixture to the fill neck until the level is again visible in the horizontal tube section

  5. Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated.

Notice: If the pressure cap is not tightly installed, coolant loss and possible engine damage may occur. Be sure the cap is properly and tightly secured.

If the coolant is not at the proper level when the system cools down again, see your dealer/retailer.