Special tools required:

WARNING: This page is about a different car, the 2003 BMW 525i, 2002 BMW 525i, and 2001 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.

11 4 050
13 3 061
13 3 063
13 6 051
13 6 054

NOTE: For engine oil pressure to be checked, oil pressure switch must be removed and special tools must be installed and connected.

To avoid an excess discharge of oil when removing oil pressure switch:

Unscrew oil filter cap; the engine oil flows out of the oil filter housing into the oil sump.

Installation:

Replace sealing ring.

Tightening torque. Refer to ENGINE - TIGHTENING TORQUES

Fig 1: Installing Special Tool 11 4 050 With Sealing Ring In Place Of Oil Pressure Switch

Courtesy of BMW OF NORTH AMERICA, INC.

Remove oil pressure switch.

Installation:

Tightening torque. Refer to ENGINE - TIGHTENING TORQUES

Install special tool 11 4 050 with sealing ring (1) in place of oil pressure switch.

Checking engine oil pressure with DIS Tester

Attach special tool 13 6 054 with sealing ring (1) and special tool 13 6 051 and connect to DIS Tester.

Checking engine oil pressure with pressure gauge

Install special tool 13 3 063 and special tool 13 3 061 (pressure gauge).

Start engine and check engine oil pressure.

Specified value.

Fig 2: Checking Engine Oil Pressure With DIS Tester

Courtesy of BMW OF NORTH AMERICA, INC.