TSB: Colorado Coolant Filling

This bulletin applies to 2015-2022 Chevy Colorado vehicles. It can be difficult to remove the air from the heater core using the Vac N Fill method because the radiator cap and heater core are at about the same height. If a gurgle noise persists, raise the front of the vehicle with a hoist until the cap is above the cowl. Add 400ml of coolant to the overflow bottle, and remove the radiator cap. Run the engine for an hour running the throttle up to 1500 rpm three or four times during the hour.