The engine lubrication system is mixed.

The lubrication scheme is shown in fig. 1

Oil under pressure is supplied to the main and connecting rod bearings of the crankshaft, to the camshaft bearings, to the bearings of the intermediate shaft of the ignition distributor drive and the oil pump shaft, and to the pushers

Pulsating oil supply is provided for the rocker bushings.

Oil is supplied to the rest of the rubbing parts of the engine by gravity and splashing.

ZIL-131 engine lubrication scheme

From the oil sump, oil is sucked into the oil pump through a fixed oil receiver.

Through a channel in the rear baffle of the block, a pressurized pump supplies oil to the oil filter housing.

The oil cleaned in the centrifugal filter enters the distribution chamber located in the rear partition of the unit.

From the distribution chamber, oil enters two longitudinal main channels; from the left channel, oil is supplied to the crankshaft main bearings, and from them to the camshaft bearings.

The oil flows through the channels in the crankshaft to the connecting rod bearings

A special hole is provided in the body of the connecting rod, at the moment of its coincidence with the channel in the crankshaft journal, oil is sprayed onto the cylinder wall (Fig. 1, d).

The oil removed from the cylinder walls by the oil scraper ring is discharged into the piston through the holes in the ring groove and lubricates the piston pin bearings in the piston bosses and in the upper connecting rod head.

From the front end of the right (in the direction of the car) main channel, oil is supplied to lubricate the compressor.

There are two connecting holes in the middle journal of the camshaft, when they coincide with the holes in the block (once - with each revolution of the camshaft), oil is supplied to the channels made in each head of the block.

From these channels, through the groove on the bearing surface of the rocker axle strut and the gap between the walls of the hole in the strut and the bolt passing through the strut, the oil enters the hollow axis of the rocker arms, from where the oil flows through the holes in the axle wall to the rocker bushings (Fig. 1 , b).

From the gap between the axis of the rocker arms and the hole in the rocker arm, oil is supplied through a channel made in the short arm of the rocker arm to lubricate the spherical bearings of the rods, as well as to lubricate the valves and valve rotation mechanisms, to which oil flows by gravity (Fig. 1, b ).

The rod pushers are lubricated with oil from the longitudinal main channels.

Compulsory crankcase ventilation, suction of crankcase gases into the engine intake gas pipeline through a special valve 3 installed on the intake gas pipeline.

From the valve, gases are sucked off through a special tube into the central part of the intake gas pipeline.

To turn off the ventilation system when crossing the ford, a valve 4 is installed between the tubes.

The crane handle must be vertical when crossing the ford. After overcoming the ford, the handle must be turned to a horizontal position.

When the engine is running with a slightly open throttle, under the action of a large vacuum in the intake gas pipeline, valve 3 rises, the upper stepped part of the valve enters the opening of the fitting 5 and reduces the valve flow area to the value necessary for the passage of a small volume of gases breaking into the crankcase.

When the engine is running with a wide open throttle valve, the vacuum in the intake gas pipeline drops and the valve lowers under the action of its own weight, opening the full flow area, the value of which corresponds to the passage of a large volume of gases breaking into the engine crankcase.

The valve must be cleaned using acetone or another similar solvent within the time specified in the "Maintenance of the vehicle" section.

Oil cooler tubular air-cooled, installed in front of the main radiator of the engine cooling system.

The oil cooler must always be on, and it should only be turned off when starting a cold engine when the outside temperature is below 0°C.

In low winter temperatures, the oil cooler can also be turned off. Turn off the oil cooler with tap 2 (see Fig. 1).

In all maintenance work on the engine, it must be remembered that the engine is designed to operate when immersed in water; therefore, all joints between units, regardless of the presence of gaskets in them, are sealed with sealant.


Repair of the crankshaft consists of regrinding the main and connecting rod journals to the next repair size

The hydraulic clutch release (Fig. 1) of vehicles of the UAZ-31512 family consists of a suspended pedal 19, a master cylinder 5, a hydraulic pipe 4, a hydraulic hose 24 and a working cylinder 25