Maintenance Q&A Injection questions and failing radiator caps
By Paul Abelson, senior technical editor  Q. I recently retired
my Cat-powered Pete 359. From now on it’s just for American
Truck Historical Society events and parades. I got a Peterbilt
389 with a bit more than 500,000 miles for a good price, and it
should last the rest of my career. Since Cat gave up on
trucking, I figured I’d be better off with a Cummins. It is a
550-horsepower ISX.  With my 3406 Cat, I pulled my fuel
injectors every year. They gave me clues about what was
happening inside my engine. I checked for carbon near the tips
and once found a tip that was blown off. There’s nothing in the
Cummins engine manual about pulling the injectors. Should I
still pull my injectors when I winterize? If not, why not?  A.
In the days before electronic engines, when injection pressures
were about 3,000 pounds per square inch, injectors used to load
up with soot, essentially carbon residue mixed with unburned
diesel and motor oil. It would bake onto