Removal in cars of models 520i, 523i, 528i (M52 engine)
Attention: To check the operation of the safety valve, it is enough to first remove the oil pan, the oil pump does not need to be removed.
Remove oil pan.
Loosen the nut and remove the oil pump sprocket from the chain. To do this, loosen the chain tensioner (push back).
Attention: The nut has a left-hand thread, so it must be turned to the right.
Unscrew bolts -arrows- for oil pump and remove oil pump. Pay attention to the 2 guide bushes in the cylinder block for reassembly.
Slide the oil pan back and remove.
Examination
If necessary, dismantle and clean the oil pump in the following sequence: unscrew the fastener -2- of the inlet pipe -1-, unscrew the fastener -4- of the pump cover -3- and remove the cover. When doing this, make sure that the 2 guide bushes -5- are not lost.
Check rotors -6- and -7- for wear and marks, replace these parts if necessary.
Prescribed measured values:
- maximum radial clearance between outer rotor -7- and pump housing -8-: 0.18 mm;
- maximum axial clearance of the inner rotor: 0.08 mm;
- maximum axial clearance of the outer rotor: 0.09 mm.
Remove retaining ring -9- and pull out safety valve consisting of parts -10- to -13-. Measure free length of spring -12-, replace if necessary. Prescribed spring length: 84.1 mm.
Attention: Always renew O-ring -11-. Carefully insert the safety valve and secure it with the circlip.
Screw on inlet pipe with new seal -14-, lug on seal must point towards oil receiver.
Lubricate all parts with engine oil, tighten the oil pump cover bolts to 10 Nm.
Installation
Attach oil pump, tighten bolts -15- to 20 Nm. To center the oil pump relative to the crankcase, 2 guide bushings must be located between them. Insert sprocket -16- with applied chain -17- and tighten fastening nut -18- (left hand thread) torque 25 Nm. If removed, install chain tensioner -19-.
Tighten the mounting bolts oil pan.