I am looking at a 1999 T-800B Kenworth with a CAT C-12 410 hp with 680,000 miles on it for $21,000 which isn't a bad price I don't think.

My question is this, I was talking to a guy and he told me cat motors are tough, good, and very expensive to repair. He told me there is one cat motor that people say to stay away from and he could not remember.

Anyone give me advice on this deal, especially the CAT Motor?

The Kitty CAT to stay away from was the 3176 undersized basically a 9 liter motor tiring to do a 12-13 liters work. Star Trans out of Morton IL fell in love with them so did Millis in the mid 90's they were replaced with the C-10 and 13 then the C-12. Cats are not anymore expensive to repair than anyother engine just the fact CAT requires all parts back as cores for the most part. That way they can analyze why it broke and then improve it. Problems on Cats not very many JUST USE CAT FILTERS with what you haul they will keep that motor clean. Get it dynoed dump the ECM and pull an oil sample and see what they show sounds pretty decent.

Actually, the C13 is the replacement for the no longer available C12.

The C12 was produced from 1995 to 2003.

Externally the C13 looks just like a C15, but it is a 12.5 liter engine and the C15 is 15.2 liter.

We've got a bunch of C12's, C13's and C15's where I work, and they're all good runners.