Warning
Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes.
1. Clean the radiator cap negative pressure valve and tha sealed part.
2. Inspect the crack or turn over on sealed of the radiator cap.
3. Fill the radiator cap test adopter with the water or the engine coolant to the full level and attach the radiator cap to the adapter.
4. Hold the radiator cap downward and apply pressure gradually. Verify that the pressure become held for 10 s
within the specification.
Pressure
113-142 kPa
{ 1.1-1.4 kgf/cm2, 15-20 psi}

Engine coolant
RadiatorMazda 6 Service Manual: Add-On Non-Genuine Parts and Accessories
Non-genuine parts and accessories for Mazda vehicles can be found in stores.
These may fit your vehicle, but they are not approved by Mazda for use with Mazda
vehicles. When you install non-genuine parts or accessories, they could affect your
vehicle's performance or safety systems; the Mazda w ...
Mazda 6 Service Manual: No.8 brake system warning light stays on more than 4 seconds with ignition
switch on
Diagnostic procedure
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while doing the inspection to discover whether
poor contact points are the cause of any intermittent malfunction. If there
is a problem, check to make sure co ...