Pressure Relief Valve Inspection

WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

Install the manifold gauge set.
Start the engine.
Turn the fan switch and A/C switch on.
Verify the high-pressure side reading of the manifold gauge.
Check for leaks from the pressure relief valve using a gas leak tester.
- If not as specified, replace the cooler hose (HI).
  
  Fig 1: Pressure Relief Valve Specifications
  Courtesy of MAZDA MOTORS CORP.