Another source for heat is the steering column
I didn't like the factory style steering column seals so I made one using a heater hose. It seals a lot better.
check that your cowl to hood seal is installed properly. I have seen many seals installed backwards. Also check cowl lip above the wiper motor, that is a weak spot
The cowl seal is pointing the correct direction and when I installed the new one, I even used an door edging that fits perfectly inside of it to stiffen it up more. You just gave me an idea....I 'll smear some grease along the top edge, close the hood and after I open it check to see if any didn't transfer to the hood.
If your theory about air getting into the cowl vents is correct, you should be able to test it easily enough. Do you actually feel hot air coming in through the driver vent? Does it diminish when you close that vent? I'm wondering if it isn't coming from the transmission instead. They are capable of generating tons of heat and they are close to that area. I know the dynamite should handle that but it wouldn't hurt to remove your center console to get your hand under the carpet and feel the tunnel area.
I have a manual and I placed a piece of inner tube rubber over the hole and everything is sealed up so that nothing can come from there.
The heat is coming from the driver side vent. The passenger side doesn't have any issues. I'll double check the seal above the wiper motor though.
Thanks everyone.