Volkswagen Workshop Service and Repair Manuals

Checking intake manifold change-over Test prerequisite l  Perform this test only if torque is insufficient, that is when elasticity or pulling power is inadequate. Special tools and workshop equipment required

t  Vacuum tester -V.A.G 1368-

t  Hand vacuum pump -VAS 6213- Test procedure –  Check that vacuum lines are connected correctly → Chapter and → Chapter. –  Check vacuum hoses for porosity. –  Test vacuum system for leaks. Check vacuum unit in upper part of intake manifold for leaks

–  Pull vacuum hose to intake manifold change-over unit -arrow- off intake manifold change-over valve -1-.   Note The vacuum unit for intake manifold change-over is integrated in the intake manifold and not visible from the outside. –  Connect hand vacuum pump -VAS 6213- to vacuum tester -V.A.G 1368- -connection B-.

–  Connect vacuum unit vacuum hose to vacuum tester -V.A.G 1368- -connection A-. –  Set vacuum tester to -A/B- position. –  Operate hand vacuum pump -VAS 6213- several times. Create a vacuum of maximum 500 millibar. –  Vacuum must not drop. If vacuum drops: –  Renew intake manifold upper part → Chapter. Check vacuum unit in intake manifold lower part for leaks

–  Pull vacuum hose to intake manifold change-over unit -arrow- off intake manifold change-over valve 2 -1-. –  Connect hand vacuum pump -VAS 6213- to vacuum tester -V.A.G 1368- -connection B-.

–  Connect vacuum unit vacuum hose to vacuum tester -V.A.G 1368- -connection A-. –  Set vacuum tester to -A/B- position. –  Operate hand vacuum pump -VAS 6213- several times. Create a vacuum of maximum 500 millibar. –  Vacuum must not drop. If vacuum drops: –  Renew intake manifold lower part → Chapter. If the pressure does not drop on either of vacuum units: –  Check change-over mechanism in intake manifold for freedom of movement. –  Remove intake manifold upper part. –  Repeat leak test on both vacuum units. Check whether change-over flaps move. If a fault is found: –  Renew intake manifold upper part or intake manifold lower part.