I have a strange problem nobody has been able to solve. At idle (or higher) the engine whistles. It is not a belt, bearing, etc issue. I have determined it is a whistle due to high vacuum in the crankcase. Here is how I know.

With the engine running and whistling, if I pull the dipstick I hear a whoosh as air rushes into the dipstick tube. Same holds true if I remove the oil cap on the valve cover. If I hold my hand over the oil fill cap, I can feel a good 'suck'.

Before you say "PCV", I have replaced it twice. Once with after market. And just yesterday with an actual Honda PCV valve. No change.

Any ideas why I would have such a high vacuum in the crankcase (+valve cover area)?

Thanks for your thoughts!

-Lawrence

 

Did you ever find out the issue ?
My 2005 Accord V6 coupe is doing the exact same thing .

 

 

Nope, sold it. I suspect it has something to do with the PCV valve in the front left.

 

I'm thinking the same thing... I replaced the air intake tube and cleaned the throttle body.. and this issue started up.
Oh well , the hunt continues...