New PCV valve whistle?

Maybe fuel trims but comparing the new to old one?

If possible I would listen to it with a hose, prybar, stethescope etc, to confirm it is coming from the valve... sometimes noises resonate in weird ways and places from seemingly unrelated causes.
For example an old explorer I had, cleaned the throttle body and heard a whistle that wasn't there before. Turned out to be a leaking brake booster from under the dash. I swore it was from the engine bay but after checking everything that was it. My best guess to what happened is maybe cleaning the throttle changed the air flow dynamics in the right way to make it sing. I don't feel it coincidentally failed at the same time because long before I was watching fuel trims and playing with live engine data since I was an apprentice at the time and wanted to get an idea of what was a "normal" running engine and noticed my fuel trims long term were both +6 and +7 for their respective banks but wasn't throwing a code so I didn't really look for a cause but, after replacing the booster the fuel trims sat around +1 and +3 and the whistling stopped

 

Ok thanks for the info I’ll see if I can’t isolate it. It’s so faint I’ve just been unsure if it was just the difference between a new and old part. My wife couldn’t hear it but I do just because I hear it run everyday.

 

You can also try squirting some wd40 into the new pcv valve. Yer old one likely has some goop that may be deadening the whistle.

Assuming that the new valve is sealed just fine, I'm wondering if you might have high crankcase pressure caused by blow-by, overfilled oil, obstruction of vacuum or, you know, whatever you have reason to suspect. Scary guess. you might also try subbing out the clamp on the new hose with a regular screw-tightened hose clamp from the hardware store (recommend stainless for classyness)

Mixing up OE style hose clamps, even if they look the same, can lead to bad fits..

Had a trans cooler line blow off a radiator as a likely result of that mistake. One torque converter later, I'm very mindful of my hose clamps