Wastegate Actuator: Testing and Inspection

Checking the turbo pressure regulator

WARNING: Be careful if the car is warm. The coolant is hot and there is a risk of burns from the manifold.

If the basic charge pressure cannot be adjusted, check the pressure regulator as follows:






1 Undo the hose clip on the turbocharger delivery pipe and bend the bypass pipe aside.
2 Remove the exhaust manifold heat shield. The heat shield is attached with a nut and two clips on the underside.
3 Remove the three bolts securing the front exhaust system to the turbo unit.

Important
The flexible section at the front of the exhaust system should not be bent out of line by more than 70, i.e. if the front exhaust system is allowed to hang down it must not bend more than the sag caused by its own weight. If the pipe is overloaded, permanent deformation of the constituent components will result. This can cause unwanted noise, leakage and, at a later stage, damage.






4 Remove the retaining ring and unhook the pushrod from the valve's operating arm.
5 Observe whether the flap valve abuts firmly against the turbine housing. Check for carbon deposits, etc.
6 Check that the arm moves easily.






7 Refit the retaining ring and hook the pushrod onto the operating arm.






8 Attach the front exhaust system to the turbo. Grease the studs with Molykote 1000 (part No. 30 20 271).
Tightening torque: 25 Nm (18.4 lbf ft)

Important
When fitting the front exhaust system to the turbo the nuts should be tightened alternately to avoid distorting the flange. The flange must not abut against the turbo connection flange.

9 Fit the heat shield. Press the left-hand clamp on first. Smear Molykote 1000 (part No. 30 20 271) on the bolt.
10 Fit the bypass valve with pipe. Fit a new O-ring, greased with non-acidic vaseline.
Tightening torque: 8 Nm (5.9 lbf ft)