2016 international prostar isx15 450???!

I wouldn't take it. Too much idling time.

How to tell? Divide the miles by the engine hours. It's just under 30mph. An acceptable number should be close to 50mph.

Except the truck ran a lots of off roads at low speed.

 

Can you get an ECM report on it? might help with a decision. If I remember the Idle time should show separately on it. As far as the ISX goes I have a 2015 and it been good so far. Had 450k when I bought it now got 575k. Thy are a dirty engine and produce a lot of soot, I took mine to Pittsburgh Power and had the foam cleaning done and a soot collector put on it. Also got an OPS oil bypass put on to keep thing as clean as I could.

 

The emissions controls on those engines are choking the life out of them, and the International brand isn't what it once was, plastic and skimping on metals(particularly the wiring) makes for increased problems.On the other hand the ride isn't too bad. As I always suggest, analyze the oil and take a mechanic with you. Downloading the ECM, is excellent advice and should tell you a lot.Good luck.