Valve Stem Guides

Dumb question: is replacing valve stem guides the same thing as a
"valve job", and how much on average does this cost?

 

A "valve job" usually (or should) include replacing the valves (along
with seating the valves, maybe replacing the seats).

Depending on the engine, replacing the valve seals can do wonders if
you're burning oil (and it's easy to do). I'm not sure if repacing
the guides is ever done by itself.

 

Yep- new valves or grind the old ones, maybe new seats, new keepers, new
springs (sometimes)- that's a valve job. Usually all that is done to the
guides is knurl them, although sometimes they get replaced too. Cost
varies a lot depending on engine, and how hard it is to R&R the head. If
you R&R the head yourself and take it into a machine shop, the valve job
proper will be from a few hundred up. No more than $1k even on a pretty
exotic valve train, though. But if you have a shop do all the work,
you'll pay a lot more in addition to the valve job proper.

It is on Mitsubishi 3.0 v6 engines, where the guides wear out or even
fall out of the heads well before the valves have a chance to get worn :-/

 

I assume you are speaking Pre 95 as this is not an issue 95 and later 3.0ltr

 

Falling out is not an issue after 1995. Wearing out still is.