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rrod · 03-23-2018, **(Subject: DEF pump sound getting louder )**

DEF dosing unit pump.pdf (Size: 309.75 KB / Downloads: 231)

CM2350
350k miles
DEF filter recently changed but did not fix the problem

Quote from quickserve:
“When a driver turns the key OFF, the dosing system will run a purge cycle during shutdown to prevent DEF from being left in the system and freezing in cold climates. An audible click and pumping sound will be heard from the DEF dosing unit when it is in the purge cycle. The DEF dosing unit will move its reverting valve, changing the direction of flow for the DEF. The DEF dosing unit will pull all of the DEF out of the DEF dosing control valve and line. This unused DEF is returned to the DEF tank. After a complete purge, the system will be free of any remaining DEF.”

So that sounds is getting louder. Any ideas ? I just need that pump to survive for 5 more months :s

rrod · 03-26-2018, **(Subject: DEF pump sound getting louder )**

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.

snailexpress · 03-26-2018, **(Subject: DEF pump sound getting louder )**

DEF and DPF are OEM parts. Could be different unit on Volvo or Freightliner or Pete or no DEF/DPF unit at all. This is why it's not in Quikserve.
Check the DEF dosing nozzle. If you have Insite run the test for DEF injector. If nozzle is plugged air will not come or restricted to in DEF line.

rrod · 03-27-2018, **(Subject: DEF pump sound getting louder )**

(03-26-2018 )snailexpress Wrote: DEF and DPF are OEM parts. Could be different unit on Volvo or Freightliner or Pete or no DEF/DPF unit at all. This is why it's not in Quikserve.
Check the DEF dosing nozzle. If you have Insite run the test for DEF injector. If nozzle is plugged air will not come or restricted to in DEF line.

Good idea . It would be the first real use for my Insite.
Question: in the case I would remove the dosing nozzle(valve) to clean it , Quickserve appears to suggest that the gasket have to be discarded ? That means I have to get a new gasket before this ?

snailexpress · 03-27-2018, **(Subject: DEF pump sound getting louder )**

(03-27-2018 )rrod Wrote:
(03-26-2018 )snailexpress Wrote: DEF and DPF are OEM parts. Could be different unit on Volvo or Freightliner or Pete or no DEF/DPF unit at all. This is why it's not in Quikserve.
Check the DEF dosing nozzle. If you have Insite run the test for DEF injector. If nozzle is plugged air will not come or restricted to in DEF line.

Good idea . It would be the first real use for my Insite.
Question: in the case I would remove the dosing nozzle(valve) to clean it , Quickserve appears to suggest that the gasket have to be discarded ? That means I have to get a new gasket before this ?

Gasket and white heat protection ring. Don't remember for sure but think it is in the kit.