How bad are the early paccar engines?

Never drove one. I do know a small family run reefer fleet here of about 30 units. They have been Peterbilt for two generations now. When talking about trucks he simply said quote, do not go near that engine!.
So it is little wonder when looking at used trucks with that power in them, they are priced at giveaway prices. As for the last year or two, I could not say it they are ironed out. Maybe others on here can help you.

 

Isn't the PX-8 just an ISC that has Paccar written on the valve cover?

 

PX engines are re-branded cummins. PX9 is an ISC PX7 is a ISB.

Probably needs a set of injectors, dpf cleaned and egr system cleaned. They were kinda bad for needing injectors and faceplugging the doc.

 

Everytime I hear bad things about that motor it is always in an application were it is to small and working way to hard for the work it is asked to do.

 

There's an old rule about throwing out good money after the bad. Buyer beware. Here's a little clip from a guy with hands on experience. Note what he says about the emissions system late in the video.