my truck was manufactured in 06/2018 and sat on the lot till about a week ago, i have heard DEF can expire and i am about to undergo my first regen. I am worried it may have expired and that i should evacuate it and refill with new.

With the amount of milage i put on my vehicles in a year the tank is likely to last me another year.

any opinions ?

The SCR uses DEF at it's own pace, that is, DEF usage is not tied to the regen in the DPF. It might use more (or less) DEF during regen, but it is still using it regardless of regens. WRT replacing what is left in the tank, I do not know, but interested in hearing opinions.

I read up on what the 6.7 guys do and they siphon it out, i think ours might be different tho as i tried to feed a hose down it and there is a hard "stop" where it wont go any further and its still not below the fluid level and dry. Its probably some sort of a filter screen to stop **** getting in there, when i pulled the hose out there was crystals smooshed on the end which is a sign of old DEF

might try a smaller OD hose and a vacuum pump tmrw.

Vehicles are shipped from the factory with minimum def fluid, which should be filled just prior to sale. When did you buy it?

I can't seem to edit the post but realize you just bought it. It should be fresh fluid in there.

phew, thats a relief.. Thanks for the info