2005 yukon

I have a 2004 GMC Yukon Denali XL with the 6.0. I am having over heating issues with it. We had temps sub zeros for two weeks straight and it over heated bad. The passenger side head was warped so I had bit sides milled and pressure tested. All is well on that end of things. I have reassembled everything but am still having overheating problems. I removed the thermostat and ran it like that, but still overheating. I have bled the coolant system until it was boiling out of the reservoir. Not sure where to go next. At a loss any suggestions would be wonderful.

Is the issue has already been resolved?

I had 05 Yukon Denali 6.0 for 2 years I added 1pint of antifreeze to the res. finally took to the local dealer because there was nothing on the ground and nothing in the oil. The mechanic called me within an hour said there’s a service bulliten that the heads crack under the spring you can have then milled and pressure tested but 99% of the time it wont show a leak until there bolted back on and run for awhile he said
You need brand new heads or you can change your oil every 1500-2000 miles because thats where it’s going. I changed my own oil and believe me you cannot see it but it will let you know as the viscosity brakes down when starting the truck the entire motor wood knock like it was going to explode for about 1/3 minutes then the noise would go away that’s how u would no its time for an oil change. Anyway mine overheated once and after that is when all the problems began. I believe its a cast iron block with aluminum heads heads are spamed 367 i think never fixed it sold the truck as is with 206,000 miles drove it 40,000 miles like that and it ran fine when i sold it. Oil got to expensive.

I had the same issue. I had to change the plastic connection in the hoses and the cap because they all had pin holes in them and once I did that I have had no more over heating