Daddy

Whoever said "they're not really that bad" can shove it. These are the absolute worst things to happen to trucking -- and our ability to even make a living. When we added EPA 10 trucks with DPFs and SCRs to our fleet, we spent the next 11 months having to learn about them almost daily as one visit to a shop after another sucked away every bit of the truck's revenue and more. Nobody deserves this. These systems are simply not reliable, and even dealer techs misdiagnose their problems regularly, meaning one derate after the next, and one return visit after the next. It's just so fun having your credit cards maxed out and your home equity maxed out to keep a few fault codes away. You don't clean the air by bankrupting hard-working people. The morality of that idea is nonexistent.

Couldn't quiiiiite be sure of where that white crusty joint you're referring to is, but clearly it's well past the flexpipe we've been talking about. If it's PAST the outlet nox sensor, I would hardly worry. The system won't be paying attention to it. To figure out where the outlet nox sensor is, follow the top of the tailpipe to the first wire you see. That'll probably be it.

This problem has been covered on another forum also. I looked for pan cracks but didn't find any. I believe the problem was the flexpipe between the DPF and SCR box. Not that I can locate a crack on it while inspecting it, but in thinking about it, I realized it was the only thing it could have been. ("It" being the cause of having 2 pounds of DEF crystals stacked up between the dosing valve and where the flexpipe begins.) And if you think about it, cool atmosphere has maybe twice the pressure as a 500-degree exhaust pipe, so if there's a hole in it, the atmosphere is going to PUSH its way into the exhaust flow And guess what. When a spray of DEF hits that intruding air, it crystallizes. The other thread is here: http://www.thetruckersreport.com/truckingindustryforum/threads/doser-valve-issues.265189/