Tab. 1. Possible malfunctions of the cooling system, their causes and solutions
Cause of malfunction | Remedy |
The engine gets very hot | |
Low coolant level in expansion tank | Add coolant |
Faulty thermostat (valve stuck in closed position) | Replace thermostat |
Faulty water pump | Check pump and replace if defective |
Radiator core clogged with dirt and insects | Wash the outside of the radiator core |
Radiator tubes, hoses and engine cooling jacket clogged with scale and sludge | Flush the cooling system and fill with fresh coolant |
The electric fan does not turn on due to a break in the electrical circuits of the sensors, failure of the sensors, relay or fan motor | Check and repair electrical circuits. Replace sensors, relay or fan assembly if necessary |
Damage to the valve in the plug of the expansion tank (permanently open, causing the system to be at atmospheric pressure) | Replace expansion tank cap |
The engine overheats, cold air comes out of the heater | |
Excessive drop in coolant level due to a leak or damage to the cylinder head gasket, causing vapor lock in the engine water jacket | Repair any coolant leak. Replace damaged cylinder head gasket |
The engine does not warm up to operating temperature for a long time, the thermal regime during movement is unstable | |
Faulty thermostat (valve stuck open) | Replace thermostat |
Constant decrease in coolant level in the expansion tank | |
Leaky radiator | Replace radiator |
Expansion tank leaking | Replace expansion tank |
Coolant leaks through leaky pipe and hose connections | Tighten hose clamps |
Damaged water pump seal | Replace water pump |
Insufficiently tightened cylinder head bolts (during a long stop on a cold engine, a coolant leak appears at the junction between the block head and the cylinder block; in addition, traces of coolant may appear in the engine oil) | Tighten the cylinder head bolts to the required torque (cm. Replacing the cylinder head gasket) |
Coolant leaking through a damaged intake pipe gasket or cylinder block water jacket plugs | Replace the damaged gasket, restore the tightness of the plugs |
Heater radiator leaking | Replace heater core |
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