Hey eveybody, first time post, have loved being a member and reading all the good info on this site. I have a 01 D/A w/ @ 53,000 on her. The other day as I was backing into my driveway I noticed a liquid trail. When I stopped and let the truck run, coolant was just pouring out of the reservoir overflow tube. What would be causing pressure to build up, and is it serious. Thanks for any input, and for such a great site!

FISH, It could be a cracked head, blown head gasket, broken injector seat.......either way, it sounds like you need to visit your friendly G.M. tech. Of course after you have checked the obvious. (water-in-oil / over-filled coolant / thermostats, etc. ) The press. you refer to comes from cylinder pressure getting to the coolant system. Keep an eye on that water temp. Good Luck!! Ed.

Well thought I would update. Took truck to dealer and they have it for a couple of days call me and say its two bad thermostats, ok I said, and I tell them about this site and how all the research I did here showed it was most likely a Head gasket issue. They say that they have to follow GM's procedures, ok I said. Picked up truck and drove about 6 miles to a station to fill up and what do ya know coolant overflowing, get it back to dealer. Monday comes and they say they are going to replace all of the injector sleeves. I go in and talk to the tech, he seemed like a good guy who cared about doing a good job. This takes the next 5 days, get the call last Friday they have it back together, started it up took a little while, but the resivoir pressureized. Now they will pull the heads.
Get the call today, head gasket looked ok, but the Head was warped. New Heads on the way.

Just thought I'd share. This truck has been good to me so far, have enjoyed it greatly. Is there anything I should be on the look out for, or any other potential problems that this episode could cause in the future.

Once again thanks for any imput and for a great site