Caution
To avoid corrosion use only GM Radiator Anti-freeze 19 40 656 (90 297 545).
Remove
Radiator cap from a cold engine.
Inspect
Check coolant level is up to MAX mark on reserve expansion tank and filler neck of radiator.
Top up if necessary then run engine until warm.
Check coolant level. If necessary top up coolant to filler neck of radiator.
Install
Radiator cap.