R&R DEF Head

[WinePress]

I need to replace my DEF head. Looking for any tips on this project. Looks like I will need to drop the tank and also jack up the rear end to get the tank down.
This is on a 18 DS FL chassis. Error code is bad DEF quality despite flushes and a cleaner additive.
Thanks in advance.

 

[Jonas]

Before dropping the tank, I’d make absolutely sure the DEF quality fault is actually being caused by the DEF head. On these trucks, wiring/connectors, the quality sensor and contamination can all trigger the same type of fault.
If you’ve already confirmed the head needs replacing, I’d recommend draining the tank completely and cleaning it out while you have it down. Inspect the DEF lines and connectors carefully for crystallization or corrosion, and use only the correct DEF afterward.
Having the rear supported properly and plenty of room underneath will make the job much easier. Take plenty of pictures of the line routing and connector locations before disconnecting everything.
Hopefully someone with a 2018 DS FL chassis can confirm whether the tank actually needs to come completely out or if there’s enough clearance to access the head without dropping the whole assembly.

 

[jagpot]

Before dropping the tank, I’d make absolutely sure the DEF quality fault is actually being caused by the DEF head. On these trucks, wiring/connectors, the quality sensor and contamination can all trigger the same type of fault.
If you’ve already confirmed the head needs replacing, I’d recommend draining the tank completely and cleaning it out while you have it down. Inspect the DEF lines and connectors carefully for crystallization or corrosion, and use only the correct DEF afterward.
Having the rear supported properly and plenty of room underneath will make the job much easier. Take plenty of pictures of the line routing and connector locations before disconnecting everything.
Hopefully someone with a 2018 DS FL chassis can confirm whether the tank actually needs to come completely out or if there’s enough clearance to access the head without dropping the whole assembly.

Ours is a 2014 and we did not have to drop the tank. The guy just went slow and came up underneath and over the top of the tank connecting and disconnecting one thing at a time.