Coolant Circuit Flow

WARNING: This page is about a different variant/trim than selected.

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

From the variable coolant pump, engine coolant flows through the cylinder block and the cylinder heads to the engine coolant outlet tube. Some of the engine coolant in the cylinder block is diverted through the oil cooler before returning to the engine coolant outlet connector.

From the engine coolant outlet tube, the majority of the engine coolant flows to the thermostat. Either directly or through the radiator, depending on the temperature of the engine coolant and engine speed. The remainder of the engine coolant flows through the Exhaust Gas Recirculation (EGR) coolers and the heater circuit to the thermostat. From the outlet of the thermostat the engine coolant flows to the engine coolant inlet tube on the left side of the cylinder block and back to the variable coolant pump.

A separate hose from the radiator allows extra-cooled engine coolant from the radiator to flow through the Automatic Transmission Fluid (ATF) cooler. The engine coolant from the ATF cooler returns to the system through a connector in the radiator lower hose.

The charge air cooling system is operationally independent of the engine cooling system, but connected to it at the radiator upper hose. When the charge air coolant pump is running, the engine coolant flows from the charge air coolant pump outlet through the charge air cooler, the charge air radiator and back to the charge air coolant pump inlet connection.