Bimetal Vacuum Switching Valve (BVSV) "A"

Fig. 38 Testing BVSV Cold Position:

Fig. 39 Testing BVSV Hot Position:

FEDERAL AND CANADIAN MODELS

1. Drain coolant from the radiator into a suitable container.
2. Unscrew and remove the BVSV from the intake manifold.
3. Cool the BVSV to below 77°F in a pan of cool water. Fig. 38
4. Check that air flows from pipe J to pipe L.
5. Heat the BVSV to above 106°F with hot water. Fig. 39
6. Air should flow from pipe J through pipe K.
7. If not as specified, replace the BVSV.
8. Apply a suitable sealant to the threads of the BVSV and reinstall in the intake manifold.

Fig. 7d Testing EVAP BVSV Closed Position:

Fig. 7e Testing EVAP BVSV Open Position:

CALIFORNIA MODELS

1. Drain the coolant from the radiator into a suitable container.
2. Unscrew and remove the BVSV.
3. Cool the BVSV to below 25°C (77°F) with cold water. Fig. 7d
4. Blow air into either inlet pipe and check that air does NOT pass through valve.
5. Heat the BVSV to above 41°C (106°F) with hot water. Fig. 7e
6. Blow air into either inlet pipe and check that air does pass, (valve open).
7. If a problem is found, replace BVSV.
8. Apply a suitable sealing compound to the BVSV threads and reinstall.
9. Refill the radiator with coolant.