Lubrication system characteristics (BMW 3 Series E21)

The engine has a pressure lubrication system. An oil filter with a safety valve is connected in series to the main oil line of the engine immediately after the oil pump. The gear-type oil pump is driven from the helical gear of the intermediate shaft by an extension of the distributor shaft. The oil sump is stamped from sheet steel.

In normal engine condition, the oil pressure in the lubrication system at a temperature of +80°C at idle should be within 0.5-1.0 kg/cm² and at maximum crankshaft speed 5-6 kg/cm². If the pressure drops below the permissible value, the control lamp lights up.

Oil pump

Pump body depth, mm: 19.2^+0,06_+0,3.

Gear height, mm: 19.2^-0,020_-0,041.

Maximum axial clearance of gear, mm: 0.11.

Permissible clearance between gear teeth, mm: 0.2436.

Opening pressure of the pressure reducing valve installed in the pump cover, kg/cm²: 8-9.

Length of coil spring, mm: 44±0.2.

Drive shaft diameter, mm: 15—8.011.

Diameter of the hole for the drive shaft in the pump body, mm: 15^+0,043_+0,016.

Lateral clearance between the teeth of the gears of the pump drive shaft and the intermediate shaft, mm: 0.016-0.054.

Oil filter

Brand and type: Purolator PC 253, Guiot GH 2870 or Purllux LS 171.

Opening pressure of the bypass valve, kg/cm²: 2.2±0.3.

Length of the pressure reducing valve spring in a free state, mm: 68.

Installation length of the pressure reducing valve spring, mm: 66.5.

Plunger length, mm: 35.

Motor oil

Lubrication system capacity, l: 4.5 (including 0.5 l in the oil filter).

Oil used: HD SAE 10W40.

Replacement frequency: every 7500 km or at least twice a year with replacement of the oil filter.

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