I had blown head gaskets on a '02 3.4L. After removing the heads I saw two cylinders with water in them and some rust. The machine shop reworked the heads and I decided to pull the short block and have it cleaned and honed. The shop recommends boring and new oversized pistons because of a couple of small spots on two cylinders that are still discolored (blackish), which they say is due to the rust. The engine sat for over 9 months after the heads blew. Although this NAPA dealer has a decent reputation in town, I have been a little uncertain about their recommendations due to a couple of mistakes they made related to the heads. My question is would you spend the extra $250 to have it bored and new pistons in this situation even though they say the bore diameter test was fine?

what kinda mistakes are we talking, have they done much work on 3.4s? not that boring a motor is any different from a toyota 3.4, to a GM 5.7 ect, but what more what im getting at, is if they made some small minor mistakes with like ordering the wrong parts or installing the parts wrong ect and if was like the first or second 3.4 they had done, then that could be a mute issue... cause like a said, boring is boring, it doesnt matter what motor it is, as long as you keep it within spec you are fine, if they can and have bored other motors just fine i see no issue with them boring your motor, and yeah i can see their reasoning for wanting to bore. if you opt not to have it bored, it might void any warranty you could potentially get if you do what they recommend. -basically if you forgo the bore job, and something happens down the road they could say "to bad, you didnt do as we recommended and told you this was a possibility..." its not like they are trying to sell you a new muffler and springs to make get a warranty for your motor ect.

Thanks for the prompt reply. Excellent point about the warranty. I will clarify that with them on Monday. One of their "mistakes" was taking the valve caps, etc. out of my carefully labeled plastic bags and mixing them together telling me that they were all the same. They found out differently upon reassembling and took another two weeks to "figure out" the right placement. They also told me prior to cleaning or honing that the cylinders needed to be bored although they had not taken any measurements. He said he could "look at it and tell". However, after honing and measuring they said the cylinders were in spec, however, they would still bore it as the discolored places would probably allow oil to pass the rings. The engine has 220K and I intend to drive it until it cannot be resuscitated. I could pay the extra money, but, would rather not if there would be no noticeable difference.