The water pump is a centrifugal type with an electromagnetic fan drive clutch, mounted on the chain cover. The pump delivers coolant to the cylinder block.
The pump is sealed by a self-tightening mechanical seal 7, which is pressed into the water pump housing 6 and onto the bearing shaft 11.
Coolant penetrating the seal does not enter the bearing, but flows through the hole into the drain cavity 9, closed with a plug. During engine operation, the fluid accumulating in the drain cavity gradually evaporates through openings 10 and 4. Steam penetrating the seal evaporates into the atmosphere through opening 4.
During operation, it is necessary to monitor the cleanliness of openings 4 and 10. To prevent premature bearing failure, the openings must be cleaned of contaminants during maintenance 2.
A persistent leak from inspection hole 10 of the drain cavity indicates a loss of seal integrity and the need to replace the water pump.
Bearing 11 is held in place in the water pump housing by retainer 3, which is screwed in tightly and punched. The bearing, with two protective seals, is filled with grease at the factory and does not require additional lubrication during operation. A stamped steel impeller 8 is pressed onto the bearing shaft.
At the front end of the water pump housing, the coil of the electromagnetic clutch 12 is fixedly mounted on a holder. Fan hub 1 is mounted on the water pump bearing shaft using a ball bearing.
When there is no voltage applied to the solenoid, hub 1, along with driven disk 13, is disengaged from pulley 2 and rotates freely at a low angular velocity. When voltage is applied to the clutch solenoid, driven disk 13, overcoming the force of leaf springs 14, is drawn toward pulley 2, and the fan hub begins to rotate in conjunction with the pulley and water pump bearing shaft. When the voltage is removed from the clutch solenoid, leaf springs 14 move disk 13 away from pulley 2, disconnecting the hub and pulley.
The electromagnetic clutch is connected to the vehicle's electrical system using connector 5. Voltage is supplied to the clutch solenoid by a signal from the control unit through a relay when the coolant temperature rises above 93 ± 2 °C, and is switched off when it drops below 91 ± 2 °C.
Main parameters of the electromagnetic clutch
- Supply voltage - 10.8–15 V.
- Power consumption - no more than 50 W.
- Transmitted torque at 12 V - at least 20 N m (2 kgf m).
- Minimum actuation voltage: 10 V.
- Transmitted torque at minimum voltage: at least 11 N m (1.1 kgf m).
- Gap between driven disk and pulley: 0.2–0.5 mm.
The water pump with an electromagnetic clutch is a non-repairable product. If the water pump or electromagnetic clutch fails, the entire assembly must be replaced.
The water pump and alternator (excluding the power steering pump) are driven by a 6РК 1275 poly V-belt from the crankshaft pulley. The water pump drive ratio is 1.11. Belt tension is provided by an automatic tensioner, which ensures the required belt tension as it stretches and dampens any vibrations that arise in the drive vibrations.
The tensioner requires no maintenance or adjustment during operation. In addition to eliminating the need for belt tension adjustment, the use of an automatic tensioner increases the service life of the accessory drive belt and the service life of the water pump, alternator, and tensioner roller bearings.
Replacing the ZMZ-40524 Engine Coolant Pump
Drain the coolant from the cooling system. For better access, remove the radiator.
Loosen the radiator outlet hose clamp.
Removing the outlet hose from the water pump outlet.
Loosening the hose clamp to the thermostat.
Loosen the coolant intake tube hose clamp.
And remove the hoses from the water pump pipes.
Remove the accessory drive belt.
Removing the water pump housing mounting bolt.
Removing the top nut.
Removing the lower bolt.
Remove the lower water pump mounting nut.
Remove the pump mounting bolt from the exhaust manifold side.
Removing the water pump assembly with the electromagnetic clutch that drives the radiator fan of the engine cooling system.
Remove the gasket and clean the surface of any gasket residue.
The water pump is sold with an electromagnetic clutch.
Before installing the pump, apply sealant to the mating surfaces. Fill with coolant.
Checking the Water Pump Electromagnetic Clutch
Check the rotation of the fan hub. The hub should rotate freely. If the driven disk touches the end of the pulley, the hub bearing is seized, or there is significant play in the hub bearing, replace the water pump and clutch assembly.
To check the maximum transmitted torque by the clutch, secure the water pump to the pulley and use a torque wrench to determine the torque at which the hub rotates relative to the pulley when 10 V and 12 V are applied to the clutch. The torque should be at least 1.1 kgf m and 2.0 kgf m respectively.
