How much should a heater core replacement cost?

Your Heater Core is damaged/needs replaced. The cost online for an ACDelco Heater core for the Hummer H3, is around $70.00 plus shipping. Do not buy one for $175.00 from your dealership, the heater core is also located under the passenger side glove box, you can simply remove the glove box and locate theheater core in it's casing there. You may want to google or do a search for how to replace heater core in hummer H3, you may come up with a video online or step by step if someone else has done this too. I am in the process of replacing my heater core for my H3 as well, I will take pictures and post online.