So now that Uncle Sam is forcing ULSD down our throats, have any of you had problems with it in your 12V 5.9s? Do you use additives to restore lubricity, and if so, which ones?

 

long term...yes a cetene booster is a good thing

on the flip side of that issue i can say this, ive ran fuel oil... diesel with small ammount of gas in it ,offroad... these motors and the p7100 are bulletproof just about

me and a tech I used to work next to "we both had a 12v" used to joke when a 12v got old to grab a bucket of shavings from the brake lathe, dump it in the crank case and it would run like brand new
now, i havent witnissed this but apparently usld grows bacteria quicker than lsd, this is a long term death for filters and injectors etc. in the newer trucks contaminated fuel is the kiss of death

short answer no-yes -and wichever brand you take a fancy too

scott