Intake Manifold: Testing and Inspection

Intake Manifold Change-Over, Checking

This check need only be performed when there is a reduction in available torque, i.e. problems with engine driveability and pulling power on acceleration, etc.

Special tools, testers and auxiliary items required







- Hand vacuum pump V.A.G1390







- Vacuum tester V.A.G1368

Work sequence
- Check vacuum lines for correct connection and or.
- Check vacuum hoses for porosity.
- Check vacuum system for leaks.

Check vacuum actuator in intake manifold upper part for leaks







- Pull vacuum hose to variable intake manifold actuator - arrow - off variable intake manifold valve -1 -.

NOTE: The variable intake manifold change-over actuator is integrated in the manifold and is therefore not visible from the outside.

- Fit hand vacuum pump V.A.G1390 to vacuum tester V.A.G1368 connection "B".
- Fit vacuum hose to actuator to vacuum tester V.A.G1368 connection "A".
- Set vacuum tester to "A/B" position.
- Operate V.A.G1390 several times. Create a vacuum of maximum 500 millibar.
- Vacuum must not drop

If the vacuum drops:
- Replace intake manifold upper part.

Check vacuum actuator in intake manifold lower part for leaks







- Pull vacuum hose to variable intake manifold actuator - arrow - off variable intake manifold valve 2-1
- Fit hand vacuum pump V.A.G1390 to vacuum tester V.A.G1368 connection "B".
- Fit vacuum hose to actuator to vacuum tester V.A.G1368 connection "A".
- Set vacuum tester to "A/B" position.
- Operate V.A.G1390 several times. Create a vacuum of maximum 500 millibar.
- Vacuum must not drop

If the vacuum drops:
- Replace intake manifold lower part or.

If the vacuum does not drop at either of the vacuum actuators:
- Check change-over mechanics in intake manifold for freedom of movement.
- Remove intake manifold upper part.
- Repeat leak tests on both vacuum actuators. Check that change-over flaps move.

If a malfunction is detected:
- Replace intake manifold upper part or intake manifold lower part.