Engine Coolant Circuit Flow

WARNING: This page is about a different car, the 2018 Land Rover Discovery Sport. However, it is still accessible from the selected car via links, so may be relevant.

When the engine is running, the engine coolant is circulated around the engine cooling system by the variable coolant pump.

At engine start-up the variable coolant pump shroud is in a closed position, blocking the engine coolant flow in the cylinder block. When required, the Automatic Temperature Control Module (ATCM) can request the opening of the variable coolant pump shroud to provide the required engine coolant flow.

The ATCM communicates via High Speed (HS) Controller Area Network (CAN) chassis systems bus with the Gateway Module (GWM).

When the engine coolant is cold, the electric thermostat is closed and the engine coolant flows directly back to the variable coolant pump.

Once the engine coolant reaches operating temperature the electric thermostat begins to open. This allows engine coolant flow through the radiator system to provide the required engine cooling.

When the electric thermostat is fully open, the majority of the engine coolant is passed through the radiator and the Automatic Transmission Fluid (ATF) cooler to the variable coolant pump. With a proportion still passing through the turbocharger, heater core, electric throttle and oil cooler.

Expansion and contraction of the engine coolant is accommodated by an air space in the coolant expansion tank and the compliance of the flexible hoses.