Leaking tank vents volvo vnl

The vents have a check valve that screws into the tank, remove them and clean them as they could be clogged and staying open or replace if defective.

 

We had an update from Volvo, an extended hose up the back of the cab, with a filter at the end. Not sure if this was the reason or not.

 

I'm having a similar issue, 2007 Volvo vvl, Cummins isx, no fuel filter behind cab. Had a tank leveling issue last year. Replaced the breather valves last year and blew out all of the lines and fittings for the entire fuel system as well as drained the tanks and flushed them out.
A few months ago the passenger side breather started leaking...not much and not enough to really worry about. 2 weeks ago I replaced the passenger valve again.
As of today the problem is much worse....when I stopped at a customer for maybe 10 minutes (200+ miles after fillup probably almost 1/4 fuel gone) there was a sizeable puddle of fresh diesel under the tank and the bottom as well as the back of the tank was wet...the hose for the breather had a drip on it as I looked at it.

The tanks seem to be draining "equally".
This is driving me nuts and if it gets any worse its going to shut me down while I take it to the shop, let them replace a bunch of unnecessary parts and then still probably have the issue.

Any ideas would be welcome. Sorry for the long post.

 

Hi, did you fix this? Just bought 2007 Volvo with same problem at the passenger side.

 

I didn't.... No one responded with any ideas.

It randomly stopped doing it.... Up until recently and it's not as bad as before? It seems like it's a cold weather thing...

I'm thinking I'm going to run some beer line tubing long and higher than the top of the tank so hopefully it doesn't leak? Just fills the tube?

Since it's a 4in tube that drops down the side of the tank I'm thinking longer and above might help? I'm sure that breather isn't supposed to let anything back in but it also shouldn't be letting fuel out like that....