Hydraulic Tappets - Rattling Noise

91bmw09

Group 11
Engine


Bulletin Number
11 06 91 (3322)


Woodcliff Lake, NJ
July 1991
Service Engineering


SUBJECT: Noisy Hydraulic Tappets

ENGINE: M50





Situation: With the engine warm at idle, the hydraulic tappets may produce a "rattling noise" even after performing the procedures outlined in Service Information Bulletin 11 05 90 (3058).

Cause: If an air tight seal does not exist between the oil pick-up pipe and the oil pump housing, air may enter into the oil circulation system, causing the oil to foam, resulting in inadequate oil pressure in the hydraulic tappets.

Correction: If the above complaint is received, the following items should be checked:

- gasket between the oil pick-up and the oil pump housing is seated properly. The installation of the gasket is directional. The latest version gasket with tab (P/N 11 41 726 104 - see illustration) should be installed with the tab on the gasket facing the rear of the engine as outlined in the Repair Manual, Group 11, page 11-50/19.


- sealing surfaces on both the oil pick-up and the oil pump housing are perfectly smooth using a machined straight edge.

- correct tightening torque (9 +/- 1 N-m/6.5 +/- 0.5 ft.lbs.) is applied to the oil pick-up/oil pump housing connection bolts.


Warranty
Information: Covered under the terms of the BMW New Car Limited Warranty of 4 Years/ 50,000 Miles.

Defect code: 11 33 90 39 00

Labor operation: 11 41 000

Labor allowance: E34 (M50) 30 FRU
E36 (M50) 42 FRU

Any questions regarding warranty coverage should be discussed with your District Service Manager.