Removal and installation the oil pressure reducing valve (VW Transporter T3)

If the lubrication system is not functioning properly, the oil pressure relief valve should be checked, as the valve piston may be jammed at the upper or lower extreme point.

When the piston jams at the top point, thickened oil in a cold engine is fed under high pressure directly into the main channel.

If, on the contrary, the piston jams at the lower extreme point, the liquid oil in a hot engine passes along the path of least resistance back into the oil pan. Result: insufficient lubrication of the bearings.

Removal

Use a wide-blade screwdriver to unscrew the plug.

Pull out the pressure spring and piston. The jammed piston can be pulled out with an M10 tap, having first screwed it a little into the piston.

Installation

Before installation, inspect the piston and bore for scoring. Carefully remove any scoring marks in the bore and replace the piston.

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