Thermostatic Air Cleaner: Testing and Inspection

INTAKE AIR PREHEATING, CHECKING

Special tools, testers and auxiliary items
- Hand vacuum pump VAG 1390

Test conditions
- Temperature regulating flap vacuum unit not leaking

Checking regulating flap
- Remove air cleaner upper section and take out air filter element.





- Place air cleaner upper section so that the regulating flap in the air cleaner lower section can be seen.
- Disconnect vacuum hose from the temperature regulator vacuum unit.
- Connect vacuum hose -3- to hand vacuum pump VAG 1390.
- Operate pump and check freedom of movement of regulating flap and function of vacuum unit.

- Regulating flap must close off cold air intake -1-.

Checking temperature regulator
- Connect vacuum hose -3- to temperature regulator (brass connecting hose or with notch).
- Start engine and run at idle speed.





- Check position of regulating flap after maximum 20 seconds.

Temperature of temperature Regulating flap position
regulator
Below 20 °C (68 °F) Cold air intake -1- closed
Above 30 °C (86 °F) Warm air intake -2- closed
Between 20° and 30 °C (68 and 86 °F) Between cold and warm air intake