semar

This was the reason for not fixing the corroded line to the rear a/c
Material 650, labor ca 1200 plus 12% taxes on labor and materials

The front a/c conditions the whole cabin, there are very seldom passengers in the rear seats

semar

@ 12
quote: there is an expansion valve behind there

could you specify the exact location, please?

The holes in the corroded high pressure line were in front of the rear wheel. The line was capped off at the front

StanVanDam

Location of the AC components are in the picture below. I am not saying the expansion valve is faulty. I am saying that this noise from behind the brake pedal has been reported here several times, and in most/all cases, the noise is from an AC component that is located in that area, reported to be the expansion valve. The sound is a byproduct of slightly low AC, not a malfunctioning AC component.

The sound is audible due to a lack of soundproofing in that area combined with close proximity to the cabin. If it sounds like a squeaky accessory drive belt or an uneven, intermittent squeal, it is likely AC-related. If you are hearing something else, it is probably not AC related.

For a single-AC system, the charging spec is 650g of R134a, +/- 50g. For a dual-AC system, the charge spec is 900g +/- 50g. You can do a basic check of refrigerant levels using the sight glass. Otherwise, use a manifold gauge set. Low pressure side should read 0.15-0.25 MPa, high pressure side 1.37-1.55 MPa, rear high pressure side 1.37-1.57 MPa. If the expansion valve is bad, the low pressure reading will drop to 0.

semar

@ 12
thank you very much for the diagram of the a/c system.
it still puzzles me where the sound is coming from. It is the loudest from BEHIND the front seat in the rear passsenger foot well (below the floor) since there is nothing above the floor. It is intermittend, - silent for days - but when it is on it is steady. It sounds when the a/c is off or on. I played around with the vent openings - made no difference. More pronounced when somebody is sitting in the back and while making a left turn. Nothing when I make a right turn.

semar

finally found the noise. It was in the suspension. When I changed from winter to summer tires I had access to the coilovers. Took a lubricant and sprayed the heck out of the top hat and the swaybar links. Noise gone.
Thanks to all who made suggestions