We have found Mazda 626 2.3L engines have a common problem with the tuner valve located on the front passenger side of the engine upper corner. See pictures below.
The noise originates from under the hood area of the vehicle. It sounds like a high pitch whistle or squeal.
To determine if the valve is faulty pinch off the vacuum hose with your fingers on front of engine at solenoid furthest to the drivers side of engine. When pinched off the noise will go away instantly.
After many attempts to remove and repair the noise with no avail we found there is no way to replace or repair the seal that is inside the intake manifold where the valve bolts up to intake. There is a little white arm that connects to the valve and on the other end connects to the tuner plate inside the intake manifold. The seal is a special seal that “floats” between these two parts. Every attempt to repair failed.
The dealership and repair shops have said you must replace the intake manifold to repair noise.
We found this is true if you buy a new one. The valve is not available from dealer. If they say it is you have the wrong one. If you can locate a used intake manifold you can get the valve on it. The correct valve has two torx screws holding it to the intake. The wrong valve has 3 screws holding it to the intake. Make sure you ask the parts person if the intake is being shipped with both valves on it if ordering the intake.
The actual fix or repair is replacing the plastic valve its self. The valve is cracked internally and the vacuum flowing through the crack in the valve creates the noise.
Tags: Mazda 626 2.3L High Pitched Squeal Or Noise Fix Repair
