By-Pass Air Control (BAC) Valve
WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.
- BAC valve is located on rear of front cylinder head. See Fig 1 .
- Ensure engine is cold. Start engine and let it idle. Idle speed should gradually decrease as engine reaches normal operating temperature. If idle speed does not decrease, check coolant hose to BAC valve. Repair as necessary. If coolant hose is okay, replace BAC valve.