Fuel switching tanks 07 Volvo

[snailexpress]

Some Volvo have small air filter in the breather line.
There is quote from another forum

"" When I followed the tube, I ends behind a bracket mounted to the side o the tank. Held in by four 10mm bolts. When took it off, to my surprise there is an air filter there ;). The filter was so clogged that when I shot air into it, it just exploded open. I had a peterbilt for years and the tube just ran off the tank vent with no filter. I did not realize that Volvo puts air filters on the air vent tubes And they are pretty good ones too.
Each tank has one. about 20 bucks at the dealer.""