Thermal Vacuum Valve: Testing and Inspection

Fig. 9 Checking bi-metal vacuum switching valve low temperature operation:

Fig. 10 Checking bi-metal vacuum switching valve high temperature operation:

1. With engine cold, drain cooling system.
2. Disconnect vacuum hoses and remove BVSV from intake manifold.
3. With BVSV below 127°F (53°C), blow air into nozzle 3,Fig 9. Air should not come out of nozzle 4.
4. With BVSV heated above 149°F (65°C), in hot water, blow air into nozzle 3. Air should come out of nozzle 4, Fig. 10.
5. Wrap sealing tape around threads and reinstall BVSV in intake manifold.
6. Reconnect vacuum hoses.