My 2000 Silverado Z71 has absolutely no heat and I can't figure out why. The thermostat seems fine because it will get all the way close to 210. Anyone else had this problem? I'm really hoping it's not the heater core. I didn't think it was because there really isn't any residue on the windshield or floor.

 

I'm not sure if this will help at all, but i may have had the same problem. my truck just stopped blowing hot air, then one day I took it wheeling without a fan(i know, stupid) and it overheated and blew apart the white plastic connector going to the heater core in the engine bay. fixed it and got my heater back (it may pe possible that overheating it blasted the junk out). so try pulling the hoses and flushing the core

 

I actually just pulled the hoses and flushed the heater core about 2 hours ago and it's blowing heat like a champ now!!