Diagnosis of malfunctions of the cooling system
Cause | Remedy |
The coolant temperature is too high, the indication is in the red area of the scale | |
Too little coolant in the circulation circuit | The expansion tank must be filled up to the mark, see subsection 5.2., check the cooling system for leaks. |
Coolant regulator not open (thermostat) | Check if the top coolant hose on the radiator gets hot. If not, remove and check the regulator, replace if necessary. |
Faulty liquid cooling pump | Disassemble and check the pump. |
Faulty coolant temperature indicator sensor | Also check the sensor. |
Faulty coolant temperature display system | Check indicator device. |
Faulty radiator cap | Check the cooling system, hydraulically test the screw cap. |
Radiator plates dirty | Remove the radiator and blow it out with compressed air from the engine side. |
The radiator inside is slagged with lime deposits and corrosion products. The radiator heats up only in the upper part, the lower radiator hose with coolant does not heat up | Replace radiator. |
The radiator fan does not rotate in accordance with the increase in the engine speed, the bimetallic plate of the hydraulic clutch of the cooling system fan is faulty | At a coolant temperature of about 90–95°C, leave the engine running at an engine speed of 4000–4500 rpm, while the fan shaft speed should clearly increase. Otherwise, check the hydraulic clutch of the cooling system fan, if necessary, replace the bimetallic plate. |