c_mayer - 1/31/2026 10:45

That is the biggest culprit of emissions issues on our combines...That's why I said we have few DEF issues, it's not a problem of the system that the tank is full of junk that's not DEF. The factory put a screen in the fill neck, and a filter on the tank breather...the fact you can't keep from jamming a dirty nozzle in it for YEARS isn't entirely on someone else. Yes, they could try and shape the tank differently so it doesn't collect trash, but show me an area trash won't lay on a combine...

The other common failure is mice chewing the DEF and coolant lines going to the DEF tank from the engine...yeah, it's a DEF failure, but not caused by an emissions fault.


I dont buy that one bit. I worked as a mechanic on heavy trucks. On highway off highway etc.

Yes there were cases were contamination was an issue but in my experience less than 5% probably closer to 1%.

And every engine i service the first thing i do is def quality checks. Def is perfectly fine, yes temp sensors, injectors, nox sensors, deaf pumps, quality sensors check valves, vents you name it bad. Not from poor quality or contamination. Saying 75% is way way way off. I doubt you would even find a mechanic who works on it for a living to say even 35%.

In 2007 when tier 4 rolled out, multiple businesses went under becuase they bought a whole fleet of tier 4 cat powered trucks. And that is just local to me. The amount of parts, warranty work, service calls etc related to that junk had to have one hell of a carbon footprint.

Now from what I read between the lines about trump and emissions goes like this.

We will see a pull back on future emissions. Probably keep status quo til possibly the next administration. Maybe some software updates and future products having a less sensitive threshold for derate etc.

Maybe the biggest change we will see that effects us is the lowering the CAFE standard and possibly slightly less BS on automotive applications. Maybe elimination of stuff like auto start stop, less cylinder deactivation, and stuff like e torque that simply dont have any justifiable application other than stretching a few BTUs from the fuel.

The auto start stop is the most idiotic one of them all. They force you to buy it but out a button to turn it off.

We have active intakes, grill shutters, active air dams, and the list goes on and on to meet CAFE standards. These items are driving up the price of the product well beyond the amount of fuel you will ever save in the name of what? Added trips to the dealership that further increases our carbon foot print?

Its literally as dumb as the idea if pumping fresh air into the exhuast to lower concentration of emissions. Atleast in the 80s you could cut a belt and be done with it.

We need to step back as a whole and look at this with logic. On diesel engines common rail diesel, with the right tubing is sooo much more clean than 1990s MEUI fuel systems and fuel efficient that just implementing common rail is enough to have the clean air everyone wants. Its reliable, and without egr destroying your engine, and tail pipe emissions components costing the manufacturer and customer an arm and a leg to purchase and maintenance.

I will also say, dealers need to properly educated on DEF storage...or whoever is selling you DEF. It does NOT go bad, as much as your supplier want's you to believe. It can be stored for YEARS if done correctly. The only thing that causes DEF to go bad is if the concentration becomes far enough off the standard to cause a problem...and as long as your system doesn't have a quality sensor, then it won't even notice then unless it's so bad it can't spray enough to meet emissions.

Keep it out of sunlight, keep it from freezing, and it will store for years! If you live in Texas or Arizona and have a white tank in the bed of your truck for DEF in the summer time, you're probably going to see some DEF quality issues if you don't use that tank pretty quick!!
Chris