Was cleaning out a 90s Mack truck manual and found a wild fact about DEF

I was going through a stack of old service manuals from a closed shop in Toledo, and one for a 1998 Mack CH had a handwritten note. It said 'tried urea injection on a test rig, got 5% better mileage but smelled like a cat box.' I had no idea they were messing with Diesel Exhaust Fluid chemistry that long before it became standard. It just sat there for over twenty years. Anyone else stumble on weird pre-emissions tech notes like that?

3 comments

3 Comments

sethmitchell2mo ago

Guess they really did reinvent the wheel, lmao.

tessap982mo ago

That cat box smell probably explains why they shelved it for so long. The public would have never gone for it back then.

fionas392mo ago

My old apartment had that same smell, @tessap98.