Engine lubrication system (fig. 1) mixed under pressure and splashing

Main and connecting rod bearings, piston pins, camshaft bearings, bushings and rocker arms, pusher bushings, tappet rod tips, oil pump and drive bearings are lubricated under pressure;

Spray lubricates the mirror of cylinder liners, camshaft cams, gears of unit drives and rolling bearings.

Lubrication scheme for MAZ diesel

Oil pump (fig. 2).

Gear type, mounted on the front main bearing cap and driven from the crankshaft gear through the intermediate gear; consists of two sections - main and radiator.

MAZ diesel oil pump

The main (pressure) section of the pump supplies oil to the main oil line through a coarse filter 14 connected in series (see Fig. 1).

A bypass valve 12 is installed in the coarse filter housing (Fig. 3), which, with a pressure difference before and after the filter equal to 1.8 - 2.3 kgf / cm2 (if the element is contaminated filter), opens and part of the crude oil, bypassing the filter, enters the oil line.

MAZ car oil coarse filter

By the moment the bypass valve 12 begins to open, the signaling device contacts will close:

- at this moment, a signal lamp lights up in the office.

After the filter, the oil enters the central oil channel, and from there through the channels in the cylinder block to the crankshaft and camshaft bearings.

From the crankshaft bearings, through a system of channels in the crankshaft and connecting rods, oil is supplied to the bearings of the upper heads of the connecting rods.

From the camshaft, the oil is directed in a pulsating flow into the channel of the pusher axis and from there through the channels in the pushers, along the hollow rods and rocker drillings - to all the rubbing pairs of the valve drive.

From the central oil channel through the outer cabin, oil enters the turbocharger bearings through an additional fine filter (Fig. 4).

MAZ car oil fine filter

After the coarse filter, a centrifugal fine oil filter 1 is connected parallel to the main oil line (see Fig. 1), which passes up to 10% of the oil passing through the lubrication system.

Clarified oil is drained into the pan.

The discharge section of the oil pump is equipped with a pressure reducing valve 10 (see Fig. 1), which bypasses oil into the sump at a pressure at the pump outlet of more than 7 - 8 kgf / cm2.

A safety valve 8 is installed in the body of the radiator section of the pump, adjusted to a pressure of 0.8 - 1.2 kgf / cm2.

To stabilize the pressure, a differential valve 6 is included in the lubrication system, adjusted to the beginning of opening at 5.2 - 5.4 kgf / cm2.

Fine oil filter

CMO centrifuge for MAZ

Centrifugal type filter (centrifuge). Rotor 11 (Fig. 5) of the filter is driven by a reactive moment created by oil flowing out at a higher speed from nozzles 22.

When the rotor rotates, the mechanical particles in the oil are thrown to the inner cavity of the cap 10, forming a dense sediment, which is removed when the filter is disassembled.

The purified oil is drained into the engine crankcase.

Oil cooler

Tubular, air-cooled, located in front of the water-cooled radiator. It is turned on at an air temperature of 15 ° C and above by opening a tap located on the left side of the cylinder block.

In severe operating conditions, the oil cooler should be turned on at lower air temperatures. In all other cases, it must be turned off.

Possible malfunctions of the lubrication system and how to eliminate them

- Cause of malfunction


Low oil pressure

- Insufficient amount of oil in the lubrication system

add oil

- Dilution of oil with fuel

Fix fuel leakage in the drain line under the cylinder head covers, in the threaded connections of the injectors and in the places where the fuel lines are connected to the injectors

- Increased oil temperature

Faulty oil cooling system

- Pollution of the filter element of the coarse filter

Rinse filter element

- Clogged oil pump intake

Rinse pump intake

- Seizure of the plunger of the pressure reducing or drain valves of the oil pump

Rinse without disassembling the valve

- Wear of oil pump parts

Disassemble the oil pump and replace the manufactured parts if necessary, replace

- Wear of main and connecting rod bearings

Replace Earbuds

Reduced oil pressure in the turbocharger

The oil pressure in the turbocharger will decrease simultaneously with the drop in oil pressure in the main line with any of the above lubrication system malfunctions. In addition, there may be:

- Breakage of the oil supply pipe to the turbocharger

Replace or repair tube

- Malfunction of the oil pressure gauge in the turbocharger lubrication system

Replace pressure gauge

Change turbocharger oil filter element with filter flush

- Turbocharger bearing wear

Remove the turbocharger from the engine and send it to a workshop for repair

Water gets into the lubrication system

- Destruction of cylinder head gaskets

Replace defective gasket

- Nozzle cup nut not tightened enough

Tighten the nozzle cup nut

- Leakage of rubber rings of cylinder liners

Replace defective O-rings

- Crack in the cylinder head or block

send engine for repair