General Motors — Replace Coolant and Clean System
Maintenance · Cooling system
From a General Motors operator's manual — check it applies to your exact model before use.
Before you start
- Use soft water. Use of well water or river water may cause scaling or rusting.
- Use of water containing salt, or water in the vicinity of a mine or spa, could accelerate deposit of scale and corrosion.
Procedure
- Open the radiator cap and open the drain cocks of the engine crankcase and radiator to remove the coolant.
- Close the drain cocks and pour coolant into radiator; run the engine until the coolant is heated to about 80°C.
- If there is considerable scale or rust, pour in a cleaning solution and run the engine until about 80°C.
- Continue to idle the engine for about 30 minutes.
- After stopping the engine, open the drain cocks of the engine crankcase and radiator to drain off the coolant completely.
- Close the drain cocks and pour in coolant to rinse the system thoroughly until dirty water no longer runs out.
- Use soft water and fill until it flows out from the overflow pipe.
- After filling the coolant, run the engine for a while; after stopping, check the coolant level and replenish if necessary.
Specs & values
- Replace coolant and clean system every 500 hours.
- Heat the coolant to 80°C or higher when cleaning.
Source: General Motors operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.