How to drain the DEF tank?

[rfullen280]

Say a guy has some possibly bad DEF. How do you drain that tank (without removing it)? Is there a setting to "run" the DEF Pump? Maybe in ALFA?

 

[Riddick]

You could suck it out but I bet the fastest way is to simply remove it / drain it and then reinstall. Should be very straight forward to remove it, id guess a few minutes max!

 

[rfullen280]

That's what I thought but apparently you have to pull the crossmember. It's like they designed it to be a pain in the ass

 

[Steve_Cornell]

I pulled the pump out of the bottom of the tank and then rinsed it clean and dried it all out good... (I haven't put any DEF back in it)
you will need one of these to pull the pump.. https://www.amazon.com/gp/product/B07WT6YX6F/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

[rfullen280]

That is an excellent idea I got 10 feet of 3/8 hose and I disconnected the fittings at each junction and fish the hose all the way out to the Phil port sucked out what was left in there which is about a gallon and then pumped a gallon of freshwater back in and now I've been driving around to slash that up a bit and then I'll go back to the house and try to suck out that gallon of water and then I will do what you suggested. That seems like the best way to put it in storage

 

[rfullen280]

So, the easiest drain method is to disconnect the fill line at the tank.
I had about one gallon left in the tank of DEF when the truck was sayin "Fill DEF soon" (so needle just touching the red on the gauge ).
I put 1 gal of tap water in, drove around, then pumped a gallon or so back out.
May drop the pump later, may not.
Now I just need some lead weights for the passenger frame rail to offset the 50 gallon titan tank and the giant gaping hole between the engine and axle. IYKWIMAITYD.

 

[Steve_Cornell]

That is an excellent idea I got 10 feet of 3/8 hose and I disconnected the fittings at each junction and fish the hose all the way out to the Phil port sucked out what was left in there which is about a gallon and then pumped a gallon of freshwater back in and now I've been driving around to slash that up a bit and then I'll go back to the house and try to suck out that gallon of water and then I will do what you suggested. That seems like the best way to put it in storage

After pulling the pump I took a garden hose and sprayed the inside of the tank, I let it dry and wiped it out all out real good (once the pump is out this is easy through the 6" hole) I also unhooked the DEF injection line, flushed and blew it dry as well.
Everything DEF related is now clean and dry and ready to go if I ever need to put DEF back in the system, I am not deleted but using a tune that shuts off the EGR and DEF system.

 

[elephantrider]

so the tune you're running still allows for regens, with no def action?

 

[Steve_Cornell]

so the tune you're running still allows for regens, with no def action?

Yes, the truck still regens just uses no DEF

 

[MtnRider]

so the tune you're running still allows for regens, with no def action?

This is what they refer to as "intact" tuning vs "Compliant" (where everything still works).



.

 

[elephantrider]

intact usually means full emissions tuning. interesting to see what the longevity is for that type of tuning.

 

[Riddick]

Thanks for posting your experiences, I am taking notes. I have a few of those fuel ring removal tools laying around would be awesome if I have the right size!

 

[rfullen280]

Tools not required. They're push fittings

 

[Nifty07]

DEF is a source of ammonia NH3, injected post DPF where it is heated in the catalytic converter to convert nitrogen oxide NOx to water H2O vapour and nitrogen N2. It also has CO2 component. This is what they call SCR technology. The EGR is also part of the SCR technology and these all work to convert the toxic NOx.

During a DPF burn the injectors add diesel into the exhaust stroke and it goes to the DPF where it is burnt at a high temperature to produce ash. DEF is not used for DPF burn. Post DPF is the SCR where DEF is injected and heated in a catalytic converter.

The DPF and SCR processes are computed using various sensors in the motor and exhaust system. These include temperatures, pressures and NOx concentrations.

essentially DEF is not used by the DPF burn and the SCR sensors are used to calculate the burn. If you get a bad batch of DEF it will cause lots of burns and potentially block the DPF. This is a consequence of the SCR sensor feed back to the ECU to ensure EPA compliance.

I disconnected the filler pipe from the DEF tank, inserted a half inch hose and syphoned the fluid into a large plastic paint container. Plugged the filler hose back in and gave everything a good hosing. Took about half an hour and was easy.

I started the truck and it gave the low DEF light, warning DEF low and threatened to speed limit to 5 MPH. I drove a few miles and filled the DEF from the bowser.

Took it for a 200 mile round trip and saw a 25 minute burn. It all appears to be working as normal and will go for another run over the weekend Just to be sure.