Bi-Metallic Vacuum Switching Valve (BVSV)
- Drain coolant and remove BVSV valve. Place sensing portion in cool water , but do not allow water into valve.
- Cool BVSV to below 86°F (30°C) on Pickup models. Blow air into a pipe and check that the BVSV is closed.
- Heat BVSV to above 150°F (66°C) on Pickup models. Blow air into pipe and check that BVSV is open.
- Apply liquid sealer to threads of BVSV and reinstall. Fill radiator with coolant. If problem is found, replace BVSV.