This is more of a question for the Truck Talk forum, but I have posted there in the past and haven't gotten much response. I am a newbie getting ready to purchase my first used truck and I have a couple of questions regarding engines as most of the used trucks out there are pretty high mileage. I have been told to stay away from the 3126 Cat because it is a dry-sleeve engine and have been told that it can run about 15,000 to replace, versus a wet-sleeve overhaul which can run as little as 6,000 dollars to overhaul. I know that some are going to say that their 3126 Cat has been a gem and ran them 700,000+ miles, but keep in mind that I will be buying used and don't know how well the prior owner maintained the engine, so buying a used truck with 400,000+ miles and a dry-sleeve engine just isn't worth the risk to me. Unfortunately this has severely limited my search because it seems that almost every used truck out there around 5 years old with 400,000+ miles on it has got a blasted 3126 Cat under the hood :-( . I have found a few good used trucks with wet-sleeve engines and was looking for some input based on the experiences of veteran 0/0's. Out of the few trucks that I am looking at purchasing, the engines choices are between a Navistar-DT5300, and the 8.3L ISC-Cummins. All have about 400,000-500,000 miles on them and was wondering which is the better engine, and do either have any inherent problems that I should look out for? Also what kind of average service life do theese engines have on them? Just wondering what to expect, I do have money set aside for an overhaul if one should be needed down the road. Also some buying advice as to what to look out for when I go to look at theese trucks would be greatly appreciated, as I know that there are more factors to take into consideration than just the engine. Any input will be greatly appreciated. Thanks 
