Cooling system operation (Cooling system - L Series) (page 3 of 3)

The IRD oil cooler is located on the end face of the IRD and comprises a plate, sealed into the end face of the IRD gearbox housing. Coolant from the cylinder block passes through the plate which contains waterways and recirculates via the heater circuit. The coolant supply from the cylinder block flows through a brass connection on the rear of the cylinder block. The connection contains a thermostatically controlled restrictor which controls the flow of coolant to the IRD cooler at certain coolant temperatures. The thermostatic restrictor opens at between 80-84°C and is fully open at 96°C.

The EGR cooler, is located at the rear of the engine and is mounted on the exhaust manifold. The EGR cooler comprises a cylinder, closed at each end with two connection ports. The EGR cooler contains hollow tubes which allow the exhaust gases to pass through the cylinder. The coolant from the heater circuit flows into the lower connection on the cooler, around the hollow tubes cooling the exhaust gases, and flowing out of the upper connection back into the heater circuit.

A bleed screw is installed in the top hose to the heater matrix. This is used to bleed air from the cooling system during system filling.