Cooling System; Closed Thermostat; Open Thermostat - KTM 990 Adventure Repair Manual

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Cooling system

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Closed thermostat

The thermostat is closed if the temperature of the cooling liquid drops below 75° C. The water pump pumps the cooling liquid
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through the cylinder and cylinder heads and the thermostat .
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Open thermostat

The thermostat opens at 75° C. The water pump pumps the cooling liquid through the cylinder and cylinder heads , the
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aluminum cooler and the thermostat. The pressure in the cooling system (max. 1.4 bar) is regulated by a valve in the radiator
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cap . The cooling liquid level in the compensating tank must be between the MIN and MAX marks when the engine is cold.
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The fan switches on at 102° C.
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