Need Engine Advice

I would give the X12 a hard look if staying below 80k. Top of the line isx 12 is 1750 for tq. We ran 2010-2013 425/1650 isx 12 in the oilfield and hardly had any emission related issues

 

The "bigger is better" train of thought is old school thinking now. As you know, diesels love to be worked. Better to run a 13L hard than to barely work a 15L.

 

Freightliner is the highest seller of trucks. Their trucks almost always come with a Detroit engine like the DD15. Because they are so popular, you will find a lot of videos on YouTube showing you how to repair it yourself or even what the common problems are so you can keep an eye on the symptoms.

Whatever decision you end up making, make sure you find the maintenance manual of your truck and also your engine and read it.

 

is royal purple good or just an overpriced color purple?

One company I worked for back in 2015 when I was doing heavy haul had bought a KW T-800, with a Cummins in it. 2850 miles later it was at KW getting a crate motor put in it, also from Cummins. Far as i know personally that was the worst cummins experience I've ever heard of. It was all covered under warranty. Company I worked for took it personally against KW. They had nothing to do with cylinder liners failing in the engine, though.

Paccar the daycab I drive where I work now has that. 2013, and I think its the mx-13, could be wrong. I'd rather drive a mack, with a pussycat on a stick in front of the bulldog than drive the pete with a paccar. Bulldog or no bulldog a mack would leave the pete in the dust.