Hi, my name is Tim, and I am new to the forum and my '05 Colorado with the 3.5. On the way home from purchasing it, it kicked the PO302 code, so I read up on it and completed a compression test and leak down test. The compression test showed two cylinders were 10% low, and the leakdown test verified that those two holes had significantly more leak into the manifold. The truck has a slight hiccup in the idle but not other noticeable issues. This leaves me with several questions:
1- How long with the truck run reliably like this?
2- Is the problem typically with the intake valve seats or guides? The guides appear to be threaded-could I change them without pulling the head if I follow the procedure outlined by GM for changing the springs in the early bulletins? (Assuming I have the mechanical aptitude.)
3- Are there any casting marks to tell which heads have the updated (from GM) seats and guides? I would love to just find a junkyard head that is updated, but I can't figure out how to tell.
4- Are there any updated heads that went on the '06s? Is there a VIN number breakpoint that would tell me which 06 heads would be worth swapping out?
I have spent a number of hours reading posts-this is a great forum. If this information is out there and I have been searching in the wrong place, please point me in that direction. I know this dead horse has been beaten a good bit, but I appreciate any help and feedback you can give. I really like this truck, but I hate to spend more on a GM reconned head than it's worth!!
1- How long with the truck run reliably like this?
2- Is the problem typically with the intake valve seats or guides? The guides appear to be threaded-could I change them without pulling the head if I follow the procedure outlined by GM for changing the springs in the early bulletins? (Assuming I have the mechanical aptitude.)
3- Are there any casting marks to tell which heads have the updated (from GM) seats and guides? I would love to just find a junkyard head that is updated, but I can't figure out how to tell.
4- Are there any updated heads that went on the '06s? Is there a VIN number breakpoint that would tell me which 06 heads would be worth swapping out?
I have spent a number of hours reading posts-this is a great forum. If this information is out there and I have been searching in the wrong place, please point me in that direction. I know this dead horse has been beaten a good bit, but I appreciate any help and feedback you can give. I really like this truck, but I hate to spend more on a GM reconned head than it's worth!!