Left Side

Disconnect plug connection to check valve. Detach vacuum hose (1) from check valve.
Detach secondary air line (2) on timing case cover, top left and right.
Detach secondary air line (2) from holder and remove.

Installation:
Clean sealing surfaces on cylinder head. Replace left and right sealing rings on secondary air line (2) and apply a thin coat of grease as lubricant.
Remove left cylinder head cover. These tasks are described Cylinder Head Assembly, Valve Cover.
Remove fan clutch with impeller, refer to Cooling System.

Note: Remove VANOS adjustment unit before removing timing case cover.

If no follow-on work is scheduled after the timing case cover has been removed, remove the VANOS adjustment unit only - the splined shafts are to remain in the VANOS gear. Do not adjust the camshaft timing.
Without follow-on work: Remove left VANOS adjustment unit, refer to Camshaft, Lifters and Push Rods.
If follow-on work is scheduled after the timing case cover has been removed, remove the VANOS adjustment unit together with the splined shafts.
Remove left VANOS adjustment unit with splined shafts. This operation is described in Replacing left camshafts.





Release screw connections (1) and lay pressure accumulator to one side.
Unclip cable (2).





Carefully remove pressure control valve (1) with pliers from timing case cover.





Unclip cable from holder (1).
Release screws (2 to 4).

Caution: Take care: the gasket between timing case cover and cylinder head can drop into the engine.

Carefully remove timing case cover.





Installation:
Ensure that dowel sleeves (1) are correctly located.





Installation:
Keep sealing faces clean and free of oil.
Fill opening in cylinder head gasket with Drei Bond 1209 (or equivalent).





Installation:
Replace gaskets (1).





Installation:
Clean sealing surfaces (1) to remove gasket remnants.





Installation:
Ensure that seals are correctly seated. Fit timing case cover with inserted screw (1).

Note: It is not possible to insert screw (1) after fitting the timing case cover.





Installation:
Install holder (1).
Insert all screws and initially tighten without play.





Installation:
To tighten down screws (2), use a commercially available torque wrench or special tool 00 9 250.
Tighten screws (2) to 2 Nm.





Installation:
Tighten down screws (3) in several stages to 10 Nm.
Tighten down screws (4) in several stages to 10 Nm.





Installation:
Tighten down screws (2) in several stages to 10 Nm.





Installation:
The pressure control valve incorporates a filter.
After engine damage that suggests that the filter is contaminated with chips, it is necessary to replace the pressure control valve.
Replace sealing rings (1) and coat with oil as lubricant.
Install pressure control valve.
Assemble engine.