Chris, I'd have to say your environment is a contributing factor with that much heat your bound to have white ink problems, do you have any idea what the humidity in the print area is? if your in a dry climate it's also effecting it.The temp has been 100+ for a 4-5 day period. And my DTG is in a warehouse which is not air conditioned. I have fans circulating air, but no temp control. I have replaced the wiper blade on Friday, and rand distilled water through the system for the weekend. is it the head? Or capping station? Thanks!
One solution would be to build a free standing room big enough to house the print area and try to control the temp & humidity in it with a small AC unit and humidifier.
On another note have you looked at the bottom of your print head, cleaned it? if your wiper was bad you may have a build-up of ink on the bottom of the print head effecting the seal on your capping station, when you do a ink purge do you see all colors in the capping station and does it flow to the waste ink tank?
Hope this helps.