Diagnostics of cooling system faults
Cause | Method of elimination |
Coolant temperature too high, indication is in the red area of the scale | |
| Too little coolant in the circulation circuit | The expansion tank must be filled to the mark, see. subsection 5.2., check the tightness of the cooling system. |
| The coolant supply regulator (thermostat) is not open | Check if the upper coolant hose on the radiator gets hot. If not, remove and check the regulator, replace if necessary. |
| The liquid cooling system pump is faulty | Disassemble and check the pump. |
| The coolant temperature indicator sensor is faulty | Additionally, check the sensor. |
| The coolant temperature indicator system is faulty | Check the indicator device. |
| The radiator cap thread is faulty | Check the cooling system, perform a hydraulic test of the threaded cap. |
| The radiator plates are dirty | Remove the radiator and blow it out with compressed air from the engine side. |
| The radiator is clogged with limescale deposits and corrosion products inside. The radiator heats up only in the upper part, the lower radiator hose with coolant does not heat up | Replace the radiator. |
| The radiator fan does not rotate in accordance with the increase in 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, let the engine run at 4000–4500 rpm, and the fan shaft speed should increase sharply. Otherwise, check the hydraulic clutch of the cooling system fan, replace the bimetallic plate if necessary. |