Draining and Filling Cooling System
Ethylene glycol/water fill ratios have been established to ensure a minimum of 50 percent ethylene glycol in the coolant flush and drain procedure, and ensuring that all engine block drains and air bleeds were utilized.
The cooling system capacity for the 3100 engine is 10.9 liters (11.6 quarts); for the 3800 engine it is 10.1 liters (10.7 quarts). The coolant recovery reservoir capacity is 0.65 liters (0.68 quarts) to the COLD mark on the reservoir. The quantities listed in the filling procedure include the additional quantity to displace the air remaining in the coolant system after a static refill.
Using the correct fill ratio and the following procedures will ensure a minimum concentration of 50 percent ethylene glycol in the coolant system and simplify the customer fill task. Refer to for static fill radiator capacities. Every five years or 240,000 km, (150,000 miles), whichever occurs first, the cooling system should be drained and filled using the following recommended procedures.
CAUTION: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -possibly with explosive force - spewing the solution over the engine, fenders and the person removing the cap.
Notice: When adding coolant, it is important that you use GM Goodwrench DEX-COOL(R) or HAVOLINE(R) DEX-COOL(R) coolant. If Coolant other than DEX-COOL(R) or HAVOLINE(R) DEX-COOL(R) is added to the system the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.
DRAINING PROCEDURE
1. Park the vehicle on a level surface.
Important: This procedure significantly increases the amount of used coolant and diluted hazardous waste.
2. Remove and clean coolant recovery reservoir.
3. Remove the radiator cap when the engine is cool:
3.1. Slowly rotating the cap counterclockwise to detent. Do not press down while rotating pressure cap.
3.2. Wait until any residual pressure (indicated by a hissing sound) is relieved.
3.3. After all hissing stops, continue to rotate counterclockwise until the cap is removed.
4. Place drain pan under vehicle to collect all drained coolant.
Important: Recover coolant and store in a used coolant holding tank and submit the used coolant for recycling on a regular basis. This procedure significantly increases the amount of used coolant and diluted hazardous waste.
5. Open the radiator drain valve located at the bottom of the radiator tank. For procedures requiring the cooling system to be partially drained, opening the radiator drain valve should provide sufficient draining and no further actions should be necessary.
6. Open the air bleed vent on the thermostat housing.
7. For the 3100 engine, remove both engine block drains. The front engine block drain is located between the starter and the engine oil filter. The rear engine block drain is located by the engine crank sensor.
8. For the 3800 engine remove both block drains (knock sensors).
9. Allow the coolant to drain completely.
Important: Dispose of used coolant in a proper fashion. Never pour used coolant down the drain. Ethylene glycol antifreeze is a very toxic chemical; disposing of it into the sewer system or ground water is both illegal and ecologically unsound!
FILLING PROCEDURE
1. Close the radiator drain valve.
2. Install all engine block drains.
3. If not done previously, remove the coolant recovery reservoir and empty. Flush the reservoir with clean water, drain and reinstall.
4. Slowly fill the cooling system through the radiator neck using the following procedure:
4.1. If the coolant system has been flushed first add 100 percent ethylene glycol in the amount listed in the graphic for the appropriate engine application.
4.2. Slowly add clean drinkable water to the system until the level of the coolant mixture has reached the base of the radiator neck.
4.3. Wait for two minutes. Check the level of the coolant mixture. Add clean drinkable water if necessary to restore the coolant mixture level to the base of the radiator neck.
Notice: DO NOT use cooling system seal tabs (or similar compounds) unless otherwise instructed. The use of cooling system seal tabs (or similar compounds) may restrict coolant flow through the passages of the cooling system or the engine components. Restricted coolant flow may cause engine overheating and/or damage to the cooling system or the engine components/assembly.
Important: If the cooling system is being refilled ONLY (no flush), a 50 percent ethylene glycol and 50 percent clean water mixture should be used to fill the system. Fill the system until the level of the 50/50 mixture has reached the base of the radiator neck. Wait two minutes and recheck the level of the coolant mixture, add a 50/50 ethylene glycol/water mixture as necessary to restore the coolant mixture level to the base of the radiator neck.
5. Install the radiator cap making certain the arrows line up with the overflow tube.
6. Close all air bleeds. DO NOT over-torque the air bleed valve. The air bleed valve is made out of brass.
7. Add 0.65 liters (0.68) quarts) of a 50/50 mixture of ethylene glycol and clean drinkable water to the coolant recovery reservoir.
8. Inspect the freeze protection of the engine coolant after the engine heats up and cools down three times using a refractometer or a thermohydrometer to ensure proper freeze -37° C (-34° F) protection. Obtain the coolant mixture for the inspection from the base of the radiator neck, NOT from the coolant recovery reservoir.
Notice: The Low Coolant warning/indicator lamp may come on after this procedure. If after operating the vehicle so that the engine heats up and cools down three time, the Low Coolant warning/indicator lamp does not go out, or fails to come on at the ignition check, and the coolant is above the full cold mark in the reservoir, refer to Low Coolant Warning/Indicator Lamp in Electrical Diagnosis. If at any time the Temperature warning/indicator lamp comes on, immediate action is required. Turn OFF the engine and allow the vehicle to cool. Do not remove the coolant recovery reservoir cap at this time.