Coolant Circuit
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The coolant flow has been optimized allowing the engine to warm up as quickly as possible after a cold start as well as even and sufficient engine cooling while the engine is running. The cylinder heads are supplied with coolant in a cross-flow pattern. This ensures more even temperature distribution to all cylinders.
The cooling system ventilation has been improved and is enhanced by using ventilation ports in the cylinder heads and in the radiator. The air in the cooling system accumulates in the reservoir/expansion tank. When a pressure of 2 bar is reached in the expansion tank, the air is bled out by the pressure relief valve in the reservoir cap.
NOTE:
The ventilation ports in the front of the cylinder heads provide quicker "self bleeding" during a routine coolant exchange. The complex cooling system and the small ventilation ports require that time should be allowed after the cooling system has been filled for the air to escape.