134424-1320 ZEXEL 9 411 610 362 BOSCH OVER FLOW VALVE 9411610362 1344241320 me704255

Above Normal Heating
Low Coolant Level ... If the coolant level is too low, not enough coolant will go through the engine and radiator. This lack of coolant will not take enough heat from the engine and there will not be enough coolant flow through the radiator to release the heat into the cooling air. Low coolant level is caused by leaks or wrong filling of the radiator. With the engine cool, be sure that coolant can be seen at the low end of the fill neck or at the sight glass on the radiator top tank.Defective Temperature Gauge ... A temperature gauge which does not work correctly will not show the correct temperature. If the temperature gauge shows that the coolant temperature is to hot but other conditions are normal, install a thermometer you know is correct and/or check the cooling system.Dirty Radiator ... Check the radiator core for debris which prevents free air flow. Check the radiator for debris, dirt, or deposits on the inside of the radiator core which prevents free flow of coolant through the radiator.Loose Belts ... Loose fan or water pump belts will cause a reduction in air or water flow. Tighten belts until a 25 lb. (11,3 kg) force at the half way point between the pulleys, moves the belts .875 .125 in. (22,0 3,0 mm).Defective Hoses ... Leaks in hoses can normally be seen. Hoses that have no visual leaks can collapse during operation and cause restriction in the flow of coolant. Hoses become soft and/or get cracks after a period of time. Change hoses after a year of use. The inside can become loose and the loose particles can cause a restriction in the flow of coolant.Shunt Line Restriction ... A restriction of the shunt line from the radiator top tank to the engine front cover, or a shunt line not installed correctly, will cause a reduction in water pump efficiency. The result will be low coolant flow and over-heating.Shutters Not Opening Correctly ... Check the opening temperature of the shutters. The shutters must be open at 200°F (93°C).Defective Thermostats ... A thermostat that does not open or only opens part of the way can cause above normal heating. To test the thermostats, see the topic WATER TEMPERATURE THERMOSTAT.Defective Water Pump* ... A water pump with a loose pulley or impeller does not pump enough coolant for correct engine cooling. A loose pulley or impeller can be found by removing the drive belt for the water pump and by pushing the pulley back and pulling it forward.Air in Cooling System ... Air can get into the cooling system in different ways. The most common causes are not filling the cooling system correctly, and combustion gas leaking into the system. Combustion gas can get into the system through inside cracks or bad cylinder head gaskets. Air in the cooling system causes a reduction in coolant flow and bubbles in the coolant. Air bubbles hold coolant away from engine parts,