Cooling System: Service and Repair
Draining and Filling Cooling SystemEngine Coolant Recycling
The use of a waterless, approved coolant recycling system on the vehicle eliminates the need for evacuation. This method removes the used coolant and replaces the used coolant with approved new or with recycled coolant. When this equipment is not available use the following procedure.
Draining Procedure
Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.
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.
1. Ensure that the system has cooled, then remove the radiator filler cap.
2. Place a drain pan under the radiator drain cock.
3. Install a tube on the drain cock, if necessary.
4. Place the end of the tube in the drain pan.
5. Open the drain cock completely.
6. Allow the cooling system to drain until the flow stops. If only the radiator is drained, up to 40 percent of the old coolant will remain in the system.
7. Place a drain pan under the engine.
8. Remove the drain plug from the side of the engine block, 2.2L shown.
9. Remove the drain plugs from each side of the engine block, 4.3L shown.
- There may be more drainage from the radiator at this time.
- Allow the engine block to drain until the flow stops.
- Apply a sealer to the threads and then tighten the engine block drain plug(s).
- Tighten the engine block drain plugs (2.2L) to 15 N.m (11 lb ft).
- Tighten the engine block drain plugs (4.3L) to 18 N.m (13 lb ft).
Important: Dispose of the used engine coolant properly. Store the used coolant in a used coolant Holding Tank awaiting proper disposal or recycling. Do not pour used coolant down the drain. Dex - Cool© antifreeze is a very toxic chemical. Disposal into the sewer system or into the ground water is both environmentally irresponsible and illegal.
- If the drained coolant is discolored, flush the cooling system. Refer to Flushing.
- If the drained coolant appears normal, continue with the filling procedure.
Filling Procedure
Notice: Do not add cold water to the cooling system with the engine at or above operating temperature. Adding cold water causes rapid cooling, resulting in possible engine damage.
Notice: Do not use a solution stronger than 70 percent antifreeze. Pure antifreeze can freeze at -22°C (8°F).
1. Ensure that the radiator drain cock is closed.
2. Inspect the strength of the old coolant, before attempting to reuse. Refer to Coolant; Testing and Inspection; Procedures.
Testing and Inspection
3. When you need additional antifreeze solution:
1. For coolant use Dex-Cool© orange-colored silicate free coolant.
2. Pre-mix Dex-Cool© at a ratio of 50/50 with clean, distilled water.
3. Distilled water reduces the accumulation of scale in the cooling system.
4. Place a large mouth funnel in the radiator fill opening.
5. Slowly add the coolant mixture.
6. Fill to 1/2 inch below the radiator fill opening.
7. Start the engine.
8. As the cooling system warms up and the thermostat opens, the coolant level will drop.
9. Add coolant until the level is up to the radiator fill opening.
- Do not spill the coolant onto the exhaust system or other hot engine parts.
- Under some conditions, Dex-Cool© is combustible.
- Replace the radiator filler cap.
10. Inspect the level in the coolant recovery reservoir, add coolant if needed.
11. Test the cooling system for leaks. Refer to Cooling System; Testing and Inspection, Procedures; Cooling System Leak Testing.
Cooling System Leak Testing
Flushing
Radiator Restrictions
A dirty, obstructed, or leaking radiator core causes overheating. Scale deposits result from using hard (high-mineral) water in the cooling system. Heating these minerals causes the formation of a hard coating on the surfaces within the radiator. Scaling reduces the transfer of heat. Some hard water produces a silt-like deposit that restricts the flow of water. A radiator that is partially restricted should be removed and cleaned by a radiator repair specialist. Replace a radiator core that is plugged or has a heavy scale.
Flushing Procedure
There are different methods to flush the cooling system. Back flushing is recommended. Special equipment is available. Follow the equipment manufacturer's instructions for use.
Important:
- Remove the coolant thermostat before flushing the cooling system.
- Dispose of the used engine coolant properly.
- Store the used engine coolant in a used coolant holding tank, while awaiting approved disposal methods.
- Do not pour used engine coolant down the drain.
- Dex-Cool© antifreeze is a very toxic chemical.
- Disposal into a sewer system or contaminating the ground water is both environmentally irresponsible and illegal.