DEF pump sound getting louder

[rrod]

After reading a few things in quickserve, decided to try to find out if the return line from DEF pump to tank and the tank breathing tube were clogged up. Don’t know if this is a good idea but at least I could learn something, maybe even find out if I could install a new one myself in the worse case scenario. Still it would be better if the pump survive 5 more months, since I’m not keeping this truck.

The first thing that caught my attention was some kind of filter in the breathing tube that wasn’t mention in quickserve.
   

   


Then disconnected the return line(that goes to the tank) from the pump and applied pressured air. I could feel the air coming out of the tank breather tube. That means air went to the tank and got out , so there’s no obstruction. Will run it like that a few more days and check how it sounds.
   

   

To disconnect the line I followed the advice from @schISM in another post to squeeze the C-clips before pulling the line . At first look you couldn’t tell they had to be squeezed.