Bimetal Vacuum Switching Valve (BVSV)
- Drain coolant from radiator into container. Remove BVSV and immerse in water. Using ice, lower temperature to below 86°F (30°C). Blow air into a pipe and check that BVSV is closed.
- Heat water to above 111°F (44°C). Blow air into a pipe and check that BVSV is open. Apply liquid sealer to threads of BVSV and reinstall. Fill radiator with coolant.