Removal and installation of the oil reducing valve

In case of malfunctions in the lubrication system, the oil pressure reducing valve should be checked, as the valve piston may be stuck at the upper or lower extreme point.

When the piston is jammed at the top point, thickened oil in a cold engine is supplied under high pressure directly to the main channel.

If, on the contrary, the piston seizes at the bottom extreme point, the liquid oil on a hot engine flows along the path of least resistance back into the oil sump. Consequence: Insufficient bearing lubrication.

Removing

Loosen the plug with a wide bladed screwdriver.

Pull out the compression spring and piston. A jammed piston can be pulled out with an M10 tap, after screwing it a little into the piston.

Installation

Before installing, inspect the piston and bore for scoring. Carefully remove traces of scoring in the hole, and replace the piston.

Insert the piston and spring, install a new plug sealing ring and tighten the plug to 25 Nm.