Hi, I have a 2003 Trailblazer LT, 4.2L. I need to replace my water pump for the 3rd time. The original one failed and I replaced it with a new one from Autozone that came with a "Life Time" warranty. So after replacing this multiple times, I want to get the OEM one or one that will last... There are two that I'm looking at, AC Delco for ~$40 and original GM for ~$120. What's the difference? Also, since I've used the original bolts multiple times, I thought I'd replace them to. Does anyone have the part number of the water pump bolts?