The cooling water in the HT(high temperature) circuit cools the cylinder liners, cylinder heads and turbocharger. From the pump water is supplied to the engine manifold which is cast in the engine block. From the manifold the water is distributed to all cylinder liner sections and from each liner upwards through the cooling water channels in the liner collars. From the liner collars further into the cylinder heads. In the cylinder head the water is forced by an intermediate deck to flow along the flame plate, around the valves to the exhaust valve seats and up along the fuel injector sleeve. From the cylinder head the water is discharged via a connection piece into discharge manifold. The return water from the cylinder heads and turbocharger is supplied to the HT air cooler. In the first stage of this cooler, most of the heat from the charge air is extracted. The LT circuit water cools the charge air in the second stage. The necessary cooling for the LT water is gained from a central cooler. By controlling the LT water temperature to the inter-cooler the correct charge air temperature can be obtained. For preheating purposes, a heater circuit with a pump and heater are connected in the HT circuit before the engine. Before starting, the HT circuit is heated till about 60 °C by a separate heater The preheating of the engine is, prior of starting up and loading on HFO, of utmost importance.