Volkswagen Workshop Service and Repair Manuals

Thermo-Vacuum Valve: Testing and Inspection

Fig. 33  Thermo Vacuum Valve

1.

Remove the vacuum hose from the angled connector (vacuum source) of the thermo-vacuum valve, Fig. 33. 

2.

Remove the vacuum hose from the EGR valve.

3.

Blow through the hose.  The hose should be:

Open with coolant temperature below 45°C (113°F)
Closed above 61°C (142°F)

NOTE: If necessary, remove the thermo vacuum switch and heat or cool down with water to test.