expansion valve hissing

[jofusfarr]

I'm at a loss about this one.

My R134a A/C is operating perfectly compressor engages and pressures are right on par. 30/250 PSI at 2000RPM.

BUT, there is a hiss from the expansion valve every time compressor engages! It's only noticably really on the lowest fan setting but annoying nonetheless. I flushed system and replaced expansion valve with no improvement.

Is this typical?

[shogun]

http://www.bimmerboard.com/forums/posts/131007

[jofusfarr]

It's definitely not resonating. I can hear the refrigerant passing through it with a hiss.

Maybe I'll just use some sound proofing.

[Bo525i]

Yours hiss, mime honks and hoots quite loudly... I wish I had the hiss only

[Jeff325525]

My experience is the hissing increases with a slightly low freon charge.