Coolant: Service and Repair

COOLING SYSTEM DRAINING, FLUSHING AND FILLING PROCEDURE
1. Drain coolant from cooling system by opening radiator drain cock and removing two drain plugs from cylinder block. If coolant side of radiator cap is rusty, refill and drain system three times.
2. After drain points have been closed, refill system with fresh water only and install radiator cap. Push front "DEF" button and increase temperature to 90. This causes the water control valve to open and allows the water to pass through the heater core.
3. Run engine at medium speed until a temperature as hot as possible is reached without overheating. Cover one-half of the radiator if necessary.
4. Inspect the following points in the cooling system:
a. Radiator core for leaks.
b. Radiator air passages for plugging caused by bugs, leaves, etc.
c. Condition and tension of drive belt.
d. Condition of hoses and tightness of clamps

5. Drain system by repeating Step 1. If flush water has a rust color, repeat procedure.
6. Add equal amounts of ethylene glycol base coolant, GM 1 825-M or equivalent, and water to protect engine to at least -37°C. to -43°C. (-35°F to -45°F.).

NOTICE: The 4.5 Liter V-8 uses a coolant solution and GM coolant supplement (sealant) Part #3634621 specifically designed for use in aluminum engines. Failure to use the engine coolant supplement (sealant) and the approved coolant antifreeze could result in major engine damage. When refilling the engine cooling system, add engine coolant supplement (sealant), GM Part #3634621 and coolant antifreeze meeting GM specification 1 825-M, or those specially formulated for aluminum component protection. The above is tested and approved by Cadillac.

7. With the radiator cap removed and heater controls on maximum as outlined in Step 2, run engine at 2000 RPM for 10 minutes. Add coolant until the radiator is completely full and tighten radiator cap before stopping engine.
8. Check coolant level in the reservoir and add coolant as necessary to bring level up to the "FULL" mark.