Engine Coolant Heater
The engine heater can provide easier starting and better fuel economy during engine warm-up in cold weather conditions at or below −18°C (0°F). Vehicles with an engine heater should be plugged in at least four hours before starting.
An internal thermostat in the plug-end of the cord may exist which will prevent engine coolant heater operation at temperatures above −18°C (0°F).
If the vehicle has a diesel engine, see the Duramax Diesel supplement for more information.
See also:
What to Use
WARNING
Adding only plain water or some other liquid to the cooling system can be dangerous. Plain water and other liquids, can boil before the proper coolant mixture will.
The coolant warning syste ...
How to Check Lubricant
To get an accurate reading, the vehicle should be on a level surface.
1500 Series
A. Fill Plug
B. Drain Plug
All Except 1500 Series
A. Fill Plug
B. Drain Plug
• When the differential is c ...
Place a Call Using a Stored Number
1. Push . System responds: “OnStar
ready.”
2. Say “Call <name tag>.” System responds: “OK, calling <name tag>.”
Verify Minutes and Expiration
Push and say “minutes” t ...