(new to forum). My 05 S40 T5 started making a howling noise from the engine last week. I can't figure out where it's coming from but I do know this:

With the dipstick in, the noise is present. With it out, the noise goes away. The noise is either a howling noise or it could pass as a metal/metal noise (hopefully not a bearing somewhere). Also, if I put my finger over the dipstick hole it definitely has major suction.

Any thoughts? I'm down to 2 things and the dealer is still scratching their heads:
1) pcv system clogged somewhere?
2) turbo somehow causing pressure problems and maybe turbo is making the noise?

Thanks,
Gary

Sounds like the dreaded PCV problem being discussed at Swedespeed.com lately. They seem to clog up and cause the noise and possible oil leaking problems. Get it to the dealer ASAP before any major damage is done.

How did you resolve this?