Checking the wastegate valve, 4-cyl.

If it is not possible to adjust the basic charging pressure, check the wastegate valve as follows:

Fig 1: Illustration For Steps 1-3

Courtesy of SAAB-SCANIA OF AMERICA, INC.

1. Undo the hose clip on the turbocharger pressure 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. Undo the nuts 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 7°, i.e. if the front exhaust system is allowed to hang, it must not bend more than the sag caused by its own weight.

   If the pipe is overloaded, permanent deformation of the components will result. This can cause noise and leakage, and damage at a later stage.

   NOTE: Apply motor oil or the like to the nuts and carefully undo them.
4. Remove the clip and unhook the pushrod from the control arm on the valve.
   Fig 2: Illustration For Steps 4-6

   Courtesy of SAAB-SCANIA OF AMERICA, INC.
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. Hook on the pushrod and fit the lock clip.
   Fig 3: Illustration For Steps 7

   Courtesy of SAAB-SCANIA OF AMERICA, INC.
8. Attach the front exhaust system to the turbo. Grease the studs with Molycote 1000, part No. 30 20 971.
   Fig 4: Illustration For Steps 8-10

   Courtesy of SAAB-SCANIA OF AMERICA, INC.

   Tightening torque: 24 Nm (18 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 on the left-hand holder first. Apply Molycote 1000, part no. 30 20 971, to the stud.

   Tightening torques: 

   Locknut 20 Nm (15 lbf ft) 

10. Mount the bypass valve with pipe. Fit a new O-ring, greased with non-acidic Vaseline.

    Tightening torque: 8 Nm (6 lbf ft)