Have you tried a KoolCollar? It's a mesh collage that comes with a cold pack insert or you can use ice cubes if you're out and about. I have one for Ruckus and it helps him stay cool in the blazing summer heat when we're outside or until the car cools off. Ruckus has done the crazy panting in the car before so now I always start it and get the AC running before loading up the dogs.

Poor silky pup, heat just isn't his thing!