Lubrication System Specifications (BMW 5 Series E12)

Engines of all modifications have a pressure lubrication system.

The oil pump is rotary, with the exception of the BMW "520" from the 1978 model year and the "520i" from the 1982 model year, in the lubrication system of the engines of which a gear-type oil pump is used. The rotary oil pump is driven by a chain from a sprocket mounted on the front end of the crankshaft (from the timing drive side).

An oil filter with a replaceable filter element and a pressure-reducing valve is connected in series with the main oil line of the engine.

Excess pressure in the oil system is released by a pressure reducing valve built into the oil pump housing.

On the 525 and 528i models, the oil pan is made of light alloy and finned. On the models "518", "520" and "520i" oil pan is made of sheet steel.

Rotary oil pump

Oil pump characteristics

Pump drive on "518", "520", "520i" is carried out by a Simplex roller chain measuring 3/8" x 5/32" (the chain can be of two different lengths: normal length - red mark; extended length - green mark); on "525", "528" - single-row roller chain measuring 3/8" x 7/32".

Number of chain links: 46.



The chain tension is adjusted by selecting the thickness of the adjusting linings installed between the cylinder block and the pump body.

Since the 1978 model year, some characteristics of the oil filter and pump of BMW engines have been changed "525", "528" and "528i".

Opening pressure of the pressure reducing valve, kg/cm²: 4.8-5.2.

Clearance between the outer rotor and the pump body, mm: 0.1+0.05.

Axial clearance of the rotor in the pump body, mm: 0.035-0.095.

Gap between outer and inner rotors, mm: 0.12-0.20.

Opening pressure of the pressure reducing oil filter, kg/cm²: 2.5±0.2.

Beginning with the 1980 model year, all models were equipped with an oil pump with slightly different characteristics.

Oil pressure at idle, kg/cm²: 0.5-2.0.

Oil pressure at maximum crankshaft speed, kg/cm²: 4-5.

BMW "525", "528i" and "535i"

Clearance between the outer rotor and the pump body, mm: 0.10-0.15.

Lateral clearance between the rotor and the pump body, mm: 0.04-0.10.

Opening pressure of the oil filter pressure reducing valve, kg/cm²: 2.5.

Gear oil pump

Oil pressure, kg/cm²:

• at idle: 0.5-1.0;
• at maximum crankshaft speed: 5.0-6.0.

Length of the pressure reducing valve spring in a free state, mm: 44.

Oil filter

The filter element is changed at every oil change.

Brand:

• "518", "520", "520i": AC Delco x 18; Fram PH 46; Purflux LS 115;
• "525". "528": AC Delco AC 72 A; Fram CH 834 PL1; Purflux L178.

Opening pressure of the pressure reducing valve, kg/cm²: 2.5.

Motor oil

Oil pan capacity, l:

• "518", "520", "520i": 4,25 (including 0.25 in the oil filter);
• "525", "528": 5,75 (including 0.75 in the oil filter);
• "535i": 6,5 (including cooler)*.

* When changing oil, the capacity is 5.75 l, including 0.75 l in the oil filter.



Oil used: all-season SAE 20W50.

Oil change frequency: every 7500 km or at least twice a year.