Removal and Installation of Intake Manifold

Models 520i, 523i, 528i (M52 engine)

REMOVAL
1. Remove the air intake cover. Refer to Section Removal and Installation of Wiper Drive/Cover.
2. Disconnect the brake vacuum booster hose from the intake manifold, not from the booster. Some force is required to remove the hose.
3. Remove the cap from the fuel tank filler neck. Using a screwdriver, pry off the small covers (arrows in the accompanying illustration) and remove the screws under them. Remove the two plastic covers.

4. Disconnect the connectors of the oxygen sensor. Disconnect the connector of the VANOS solenoid valve. Refer to the accompanying illustration.

5. Remove the connector plate and move it aside.

6. Remove the cover at the intake manifold. Unscrew the positive support point (1) and squeeze the two clips (arrows in the accompanying illustration). Disconnect the base.

7. Remove the breather hose at the upper part of the cylinder block. Refer to the accompanying illustration.

Do not smoke. Risk of fire! Wipe up any leaking fuel with a rag. First disconnect the supply line (1) (from the filter), then the fuel return line (2) at the fuel distributor pipe. To do so, open the clamps. Clamps must be replaced during installation.

* On some models the supply line is connected directly to the fuel distributor pipe. During installation, replace the O-ring with a new one and lubricate it with petroleum jelly. The fuel hoses are secured by clamp brackets. In this case, tool BMW 16 1 050 is required to remove the brackets. Before installation, check the O-ring. If damaged, replace it. Refer to Injectors - Removal and Installation.

8. Disconnect the throttle body connector. Refer to Throttle Body - Removal and Installation.

* Do not disconnect the accelerator linkage and coolant hoses.

9. Disconnect the oil return hose at the oil level indicator guide tube, after opening the clamp. Refer to the accompanying illustration.

10. Unscrew the oil level indicator guide tube.

11. Unscrew the mounting bolts and remove the intake manifold support and the intake manifold coolant hose elbow. Refer to the accompanying illustration.

12. Disconnect the electrical connector (1) at the fuel tank vent valve. Lift the valve out of the holder. Press the clamp (2) and disconnect the hose. Disconnect the electrical connectors of the intake air temperature sensor and the idle air control valve at the intake manifold. Refer to the accompanying illustration.

13. Unscrew the mounting bolts and remove the intake manifold from the cylinder head.

* Make sure no objects enter the intake ports. This may cause serious engine damage.

INSTALLATION
1. Install the intake manifold on the cylinder head and tighten the mounting bolts evenly in a crisscross pattern. Before installation, check all O-rings (arrows in the accompanying illustration). If damaged, replace the rings.

2. Secure the intake manifold support.
3. Connect the electrical connectors of the intake air temperature sensor and the idle air control valve.
4. Insert the fuel tank vent valve and connect the hose.
5. Secure the positive ground terminal on the intake manifold and tighten the hex nut. Secure the cover.
6. Secure the oil level indicator guide tube to the intake manifold.
7. Connect the oil return hose to the guide tube and secure it with the clamp.
8. Install the throttle body connector. Refer to Throttle Body - Removal and Installation.
9. Connect the fuel supply and return hoses to the fuel distributor pipe. Install new O-rings and clamps. Refer to the Removal subsection.
10. Secure the breather line to the lower part of the cylinder block.
11. Connect the electrical connectors of the oxygen sensor and the VANOS solenoid valve.
12. Install the injector connector strip.
13. Secure the brake booster vacuum hose to the intake manifold.
14. Secure the two engine covers. Install the bolt caps.
15. Secure the oil filler neck cover.
16. Install the air intake cover. Refer to Wiper Drive/Cover - Removal and Installation.