When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
This is something to check, I found the vent line pinched closed on my 2000 F350 when I was trying to find out why it was leaking. When I was under my 2013 installing the hitch I checked it and found the same problem. The clip doesn't pinch it closed right away but it will happen if you don't move the clip.
Good Tip....Rep's given
Many people NEVER think to check that Vent Tube, i actually disconnect & blow air through it whenever iam under there & think about it.
Thats how my dad blew the wheel seal's out on his truck a few years ago, had mudd caked around the tip of the tube. Could not blow through it....
Just went slide my Fat butt under the truck and no way was my clip pinching the line, I could easy slide the clip up the line to the fitting. But I moved it anyway.