How does it suppose to sound when checking for working condition?

I blow on it on one side (the blue side) and I can't feel much air coming out on the other side, yet it sounds like a "trumpet with a damper", or like a whistle with a...sore throat.
Is that normal?

Part number: 433862117
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From the black side you cannot blow air in it (of course, is a non-return...)

Thanks guys.

 

Mine didn't make any noise. But suck through the black side and then through the blue you shouldn't be able to suck through the blue side. Mine fails just a wee bit when I put it on the guage. Everything works ok with mine though. I heard someone say they crack so see if you can put some pressure on it and spray it with soapy water.I just saw them for 12.00 somewhere.

 

Thanks J.
Anything that let's air through (in a car) shouldn't make that noise. If I can't suck through the black end it means is somewhat plugged.

I can just buy a universal (Motormite? brand or something like that) one at O'Reillys for like 4 bucks and use it for a while before I need to order some more parts - provided it is something wrong with this one.
If I only order this freaking thing by the time they ship it it will cost $ 20....for a darn piece of plastic.

 

Ya.. use any generic brand. Its only a check valve. The noise is from the rubber disk 'flapping' - like a balloon between your thumbs.