Nissan Repair Questions? Ask a Mechanic for Answers ASAP
You must have a leak in the firewall allowing the heat through. If the engine is overheating or running hotter than normal, than the inside shouldn't be hooter than normal unless somehow it's getting extra heat entering. Tonite, after it gets dark outside and you pull over or are already pulled over, have someone shine a flashlight either from under the hood pointing all along the firewall and you look for the light from inside or shine the flashlight from inside out and look from outside. See where the hole or leak is and if it's not obvious what is wrong, take some photos and post them so I can look at them.
Ok, that is where I would start then with shining the flashlight. Did you already do that?
JustAnswer® is not a free service. I work hard to make sure you're satisfied with my service and I only get credit for my answers based on your rating. Once you're satisfied, please leave a positive rating.