I sure hope you got your dog to the vet. Dogs can get heat exhaustion and heat stroke just like people, and heat stroke can be fatal without immediate medical support.
It's so easy to forget proper hydration and cooling during the beginning of the summer months. I'm guilty of that myself. Living in a sub-tropical region and being sensitive to heat, I have to force water and Gatorade down my throat regularly if I'm outside. Stupid me, I usually have one or two episodes of heat exhaustion before I get back in the swing of things. Same thing applies to our dogs. If they're outside all day, they need lots of water, shade and maybe even a baby pool to wallow in to cool off.
Please let us know what the vet has to say. I'm hoping it's nothing too serious.
You can give a dog aspirin...do not give him tylenol or motrin. If he is running a fever and is acting differently than normal, please take him to the vet..at 12 years old if he is overweight and panting and has not been exposed to extreme heat or been running around just prior to the panting starting it is quite possible he is having congestive heart failure, but only a vet can tell you for sure.
Good Luck to you!
Please take him to the vet right away, don't wait. It sounds as if he is distressed, overheated or having difficulty breathing.
I think at 102.7 you can safely say your dog is in the "fever" zone. Dogs' temperatures CAN vary a little around the 101.5 mark, sometimes a little higher. But over 102, although not a severe temperature, yes it is something to warrant attention.
You can't assume because he has a fever that he has a 'cold'. There could be a bunch of reasons why he's developed a fever. He does need to see the vet, to rule out a few things. It could be nothing particularly serious....but take him in anyway to get him checked out.
If he won't eat for a day or so, that's fine. It won't do him any harm. As long as he keeps drinking, otherwise he could get dehydrated.