S80 2.9 non-turbo howling due to high crankcase vacuum

mcleish · Post by **mcleish** » 09 Apr 2021, 18:10

It's so high the oil fill cap must be pried off!
Something is howling while idling, but isn't nearly as loud when accelerating.
We've replaced the oil trap, including the rubber rings - so the seal with the crankcase is good. This is when the howling started.

We replaced the MAF sensor, and I checked the throttle body gears and they look fine.

Could it be that the throttle body is just not opened enough at idle (?)

Help!

Post by **SuperHerman** » 09 Apr 2021, 23:08

Do a glove test to see if you have PCV issues. You could have a blockage in the block or on one of the lines.

That howling is pressure related from the sounds of it. Double check your work to make sure you have things routed correctly.

Post by **RickHaleParker** » 10 Apr 2021, 22:24

When you replaced the Oil trap, did you clean the Banjo bolts, ports in the block and the hoses. If they are partly restricted .. it like putting you lips together and blowing.

Do a glove test and post pictures.

mcleish · Post by **mcleish** » 11 Apr 2021, 09:47

Thank you for responding!

If I tried the glove test it would be sucked into the crankcase.

The 2 hoses from the oil trap were new so they’re not blocked. I didn’t see anything in the ports in the block. I’ve seen the videos where they are obviously clogged but I didn’t see anything in mine. Is there a way to check better? Maybe compressed air?

and I didn’t see a banjo bolt. Where is that located? This is a 2003 S80 2.9 non-turbo. I was able to replace the oil trap without removing the intake manifold.

mcleish · Post by **mcleish** » 12 Apr 2021, 21:53

I blew compressed air into the 3 ports in the block. All sounded clear, the bottom one bubbled some.

Post by **SuperHerman** » 12 Apr 2021, 22:22

Sounds like excess negative pressure.

Read this for ideas: https://gm-techlink.com/?p=7463

Post by **RickHaleParker** » 12 Apr 2021, 22:48

mcleish wrote: 11 Apr 2021, 09:47 If I tried the glove test it would be sucked into the crankcase.

Tie the glove down with a Zip tie.

mcleish · Post by **mcleish** » 13 Apr 2021, 15:52

I got a vacuum gauge and put it on the dipstick and got 15 “in Hg”, or 40 “cm Hg”.

What’s an acceptable range?

Post by **SuperHerman** » 13 Apr 2021, 21:51

https://www.underhoodservice.com/volvo- ... irst-time/

https://blog.fcpeuro.com/volvo-pcv-brea ... -diagnosis