Engine cooling system - liquid, closed type, with forced circulation of coolant

The main elements of the cooling system: water pump, radiator with curtain, thermostats, fan, fan drive fluid coupling, fluid coupling switch, expansion tank, connecting pipes.

Ural diesel cooling system

Water pump, thermostats with thermostat box, fan, fan drive fluid coupling, fluid coupling switch are mounted on the front of the engine.

The water pump is bolted to the left front of the cylinder block.

To provide access for dismantling the water pump and fluid coupling of the car fan drive, remove the radiator lining, water and oil coolers.

Water pump Disassemble only if the impeller seal is worn or damaged, or if the bearings are worn. Leaking coolant from the pump drain port indicates worn or damaged impeller seal.

Ural diesel water pump

To disassemble the water pump (Fig. 2), press the pulley 3 off the roller 10, remove the key 1 and the dust deflector 2;

Remove retaining ring 4, unpin and unscrew nut 11, remove impeller 8, sealing ring 9 and thrust ring 13;

Press roller 10 complete with bearings 5 ​​and 6 out of housing 7, press out water deflector 15 and water pump seal using mandrels, press bearings 5 ​​and 6 off roller 10.

Assemble the water pump in the reverse order of disassembly (12 - lock washer, 14 - stuffing box).

Fan drive fluid coupling (fig. 3) and fan are bolted to the front of the cylinder block.

Fluid clutch for Ural car fan drive

If the rubbing surfaces of the seal 28 and cover 27 are worn out, oil will leak, and the fluid coupling will not work, i.e., it will not transmit rotation to the fan.

To eliminate this malfunction, remove the fluid coupling from the engine.

On the removed hydraulic coupling, unscrew nuts 30, carefully remove cover 27 and replace or repair worn parts.

When the fluid coupling is completely disassembled, unpin and unscrew nut 9, remove washer and press hub 10.

Unscrew the bolts 12, carefully, so as not to damage the gasket, separate the pulley 17 from the shaft 14, complete with the cuff 7.

Remove the pulley, gasket 13 and bushing 11. Unscrew nuts 30, carefully remove cover 27, gasket 31, seal 28 and spring 26. Remove thrust rings 23 and 29.

Remove nuts 2, carefully rocking the body 18, remove the hydraulic coupling assembly from the bracket body 19.

Remove the bolts 33 and disconnect the driven wheel 32 complete with shaft 8 and casing 20 from the driving wheel 3.

Remove housing 18 from bearing 16. Using a mandrel, press bearing 6 out of shaft 14, remove thrust ring 5.

In case of emergency (breakage of bearing 16 or wheel 3), unscrew bolts 4, remove washers, press drive wheel 3 and bearing 16 off shaft 14.

Compress bearing 24 from drive shaft 22. Using a mandrel, press driven shaft 8 complete with bearing 25 out of drive shaft 22. Press bearing 25 from shaft 8.

In case of emergency, unscrew the bolts 21 and press out the shaft 8 from the driven wheel 32. If the casing 20 or the drive shaft 22 fails, replace them with new ones as an assembly.

Assemble the clutch in the reverse order of disassembly. At the same time, fulfill a number of requirements.

Before pressing wheel 3 onto shaft 14 and wheel 32 onto shaft 8, the wheels must be heated in an oil bath to a temperature of 100 ° C.

After assembling the fluid coupling, check the rotation of shafts 14 and 8.

When pressing the hub 10 onto the shaft 8, use the M8 threaded hole in the front end of the shaft.

Pressing the hub onto the shaft with a hammer is unacceptable, as the bearings may be damaged.

When rotating by the pulley 17, the shaft 14 must rotate freely, without jamming. With a fixed pulley 17, the hub 10 of the fan with the shaft 8 should rotate freely, without jamming.

Cuffs 7 and 15 should be lubricated with TsIATIM-201 lubricant before installation.

Lubricate gaskets 1, 13 and 31 with grease before installation (34 - gasket, 35 - nut, 36 - drain pipe).

Belt Tensioner

Tension device (Fig. 4) is used to adjust the tension drive belts of the fluid coupling from the crankshaft pulley.

To remove the tensioner, unscrew the nuts of the two studs securing the tensioner to the fluid coupling bracket.

In case of replacement of the pulley bearings, remove the front spring ring 6, cover 5 and locking ring 4.

Remove pulley 2 complete with bearings 3 from axle 8.

Remove the rear spring ring 6 and press the bearings out of the pulley.

Axle 8 is pressed out of lever 1 only in case of emergency.

Assemble the tensioner in the reverse order of disassembly (7 - spacer ring).

The hydraulic coupling switch (Fig. 5) is installed in the front of the engine on the branch pipe that supplies coolant to the right row of cylinders.

Ural fluid fluid clutch switch

On Ural vehicles, the switch is controlled remotely by means of a pull rod 4.

In the spring, during seasonal maintenance of the car, check the operation temperature of the hydraulic clutch switch in automatic mode (lever 13 is set to position B) in bench conditions.

If necessary, adjust the switch operation temperature by changing the thickness of the package of shims 17.

To check the operation of the switch in automatic mode, remove it from the engine.

To the “D” channel, connect a pipeline with engine oil at a pressure of 7 kgf / cm2, and lower the nut 18 and sensor 19 into a vessel with heated water.

Measure the temperature of the water in the vessel near the sensor with a mercury thermometer with a division value of 1°C. Heat the water in the vessel, stirring constantly.

The switch is adjusted correctly, if it works at a water temperature of 85-90 ° C, oil will flow from the “C” channel.

If the switch is triggered at temperatures above 85-90°C, then reduce the thickness of the package of shims 17.

If the washers fail to adjust the response temperature, replace the sensor.

In case of complete disassembly, unscrew bolts 2, remove cover 3, spring 7, washer 6 and remove spool 8 from body 5.

Unscrew bolts 1, remove cover 16 complete with plug 11 and lever 13.

Unscrew nut 18, remove sensor 19 and adjusting washers. 17. If necessary, knock out pin 12 and disconnect plug 11 from cover 16 and lever 13, remove spring 14 and retainer 15 (9 and 10 are sealing rings).

Thermostats (Fig. 6) are installed in a thermostat box located on the fan drive hydraulic clutch housing-bracket. To remove the thermostats, unscrew the bolts and remove the cover of the thermostat box.

Ural car thermostats

For thermostats, the temperature of the start of opening and the value of the full stroke of the valve 10 are controlled.

Scheme for checking thermostats is shown in fig. 7. After heating the water to a temperature of 70 ° C, its further heating is carried out with constant stirring.

Take the temperature at which the valve stroke is 0.1 mm as the beginning of the valve opening.

Thermostat test chart

The beginning of the opening of the valve should occur at a temperature of 78-82 ° C, and full opening - at 90-95 ° C. The full stroke of the valve is 6.8-8.5 mm.

The radiator assembly with fan shroud, frame and oil cooler is mounted on the first cross member of the frame.

The main malfunctions of the radiator can be: external contamination of the core, damage to the tubes, dents and cracks on the walls of the lower and upper tanks, breakage and cracks in the pipes.

Scaling may occur when water is used as the coolant.

Before repair to identify the leak and after repair to check the tightness, check the radiator with air at a pressure of 1.0 - 1.2 kgf / cm2 immersed in a bath of water.

To clean the outer surface of the core from contamination, rinse it with a hot alkaline solution.

Solder damaged outer tubes with soft solder without disassembling the radiator. Internal (not solderable) tubes can be plugged.

The number of plugged tubes should not exceed 5% of the total number of core tubes.

In case of a large number of damaged pipes, as well as to repair the fastening of pipes to tanks, open (unsolder) the upper and lower tanks and replace the pipes with new ones.

Straighten the dents of the walls of the tanks, solder the places of cracks with the imposition of patches from sheet brass with a thickness of 1.0-1.2 mm.

When using water as a coolant in the spring for seasonal maintenance, flush the cooling system to remove scale.

To do this, pour water into the system with the addition of technical trilon 20 g per liter of water.

After one day of vehicle operation, drain the solution. Filling daily with a fresh solution, flush the system for 4-5 days.



Up to -40˚

Up to -65˚


Tosol -A40


% composition Antifreeze + water

56 + 44

65 + 35

Density at 20˚ C g/cm3



When using anti-freezing liquid Tosol-A as a coolant, dilute it with soft clean water in proportion depending on the ambient temperature in winter (table).