Draining and Filling the Cooling System
DRAINING AND REFILLING
Before draining and recovering the cooling system, inspect the system. Perform any service needed to ensure that the system is clean, does not leak and is in proper working order.
Some coolant manufacturers are mixing other types of glycol in their coolant formulations; propylene glycol is the most common new ingredient. A hydrometer will not always provide a correct measurement of freeze protection when anything other than ethylene glycol and water is being tested. The degree of inaccuracy will vary depending on the proportion of other glycols present in the coolant. Hydrometers test the amount of glycol in a mixture by measuring the specific gravity of the mixture; the more ethylene glycol, the higher the float balls go, and the better the freeze protection. Because ethylene glycol and propylene glycol do not have the same specific gravities, hydrometer readings of mixtures containing propylene glycol give incorrect values. It is recommended that a "refractometer" be used when testing coolant. Refractometers test for the amount of glycol in a coolant mixture by measuring the speed of light as it passes through the fluid and are not affected by the specific gravity of the glycol.
DRAINING AND REFILLING
CAUTION: To avoid the danger of being burned, do not remove the cap while the engine and radiator are still hot. Scalding fluid and steam can be blown out under pressure.
REMOVE OR DISCONNECT
1. Install a piece of 3/8" vacuum line hose approximately 12" long on the end of the radiator drain cock.
2. Completely drain and recover the system by opening the drain cock at the bottom of the radiator, and the plug(s) in the engine block (if equipped).
IMPORTANT: Dispose of used coolant in a proper fashion, i.e., in a used coolant holding tank which is picked up along with used oil. 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!
* If the coolant is dirty, or if there are deposits in the radiator, flush the cooling system before refilling.
3. Cooling system pressure cap.
CLEAN
* Pressure cap. Test and replace, if needed.
* Cooling system filler neck on the surge tank.
INSTALL OR CONNECT
1. Close the radiator drain cock and remove hose (install the block drain plugs, if removed).
CAUTION: Under some conditions, the ethylene glycol in engine coolant is combustible. To help avoid being burned, DO NOT spill antifreeze or coolant on the exhaust system or hot engine parts.
2. Refill the cooling system with coolant meeting GM Specification 1 825-M. To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37°C (-34°F) or lower. Use a solution that is no more than 70 percent antifreeze.
IMPORTANT:
* On vehicles produced with the 2.2L engine loosen the engine coolant air bleed screw located on the top side of the engine coolant outlet. Add coolant until all air is evacuated through air bleed. Tighten air bleed screw.
* When refilling the engine cooling system, add (2) engine coolant supplement sealant pellets, GM PIN 3634621, and coolant antifreeze meeting GM specification 1 825-M.
3. Fill the surge tank to the base of the filler neck.
4. Pressure cap onto the surge tank.
* Block the drive wheels and firmly apply the parking brake. Shift an automatic transaxle to "Park", or a manual transaxle to "Neutral." Run the engine until the upper radiator hose is hot.
* Stop the engine. Observe the level of coolant in the surge tank or radiator. If not above the "Full" line, allow the engine to cool enough to relieve pressure, then carefully remove surge tank cap and add coolant.
5. Pressure cap, making sure the arrows on the cap align with the overflow hose. After servicing the cooling system, an occasional intermittent low coolant light (if equipped) may be encountered during some extreme driving maneuvers. This complaint should be eliminated by removing the surge tank cap and adding coolant to a level just at or above the "Cold Full" mark when the system is cold.