Thought I would update you all on what I have found so far. I found a Medium duty truck dealer that sells GM products, and talked to one of the tech's that works on duramax's all the time. He recommended a few things to try:
- That I get a pressure tester on the cooling system to figure out what kind of pressures I am dealing with. He said that there shouldn't be more than about 7psi in the cooling system unless it is really hot. I ended up T-ing my boost gauge into a heater line and ran it for a while. It got up to about 12 psi at 160 and I shut it off due to time constraints. I saw a good amount of bubbles coming into the bottle also.
- Call ARP about their torque procedure. GM spec for the newest gaskets with stock bolts is a four step procedure. Two torque values first and then two angle values. ARP tech on the phone stuck by their directions and torquing to 125 only one time.
- He asked about what brand and version of gaskets I used, according to merchant auto's site they are "OEM Grade C Right and Left Head Gaskets" However they didn't have any GM markings on them when I received them. As to the version I just knew they were updated because they had the rivets instead of bent over tabs as the originals had. I was informed that GM has had multiple updates on these gaskets, and the newest gaskets have a gold color on the metal portion. The ones I installed were silver. He also mentioned that he has had issues with even the updated gaskets, mostly the middle layers cracking.
