I had this same problem with a 2003 Hyundai Elantra. Mine turned out to be the AC drain. It is located just a little left of center line near the firewall. If you get under the passenger side near the door you will see the little black stub near the exhaust pipe in the center. http://www.hyundai-forums.com/index.php?showtopic=16157&hl=drain I once had a problem just like this with a 1991 Pontiac Grand Am. In my case I had to clear all of the leaves and junk that collected in and under the windshield wiper trench. When I poped the hood, there was a slight gap on each side where leaves would collect. With the hood open, the gaps were in the top corners. In my case, the leaves would become brittle and break up into small pieces which would fall down and clog the water drain channels. As it decomposed it bace a thich mud that would not clear on its own. When it rained, water would not be able to drain and would instead build up and flow through the air vents into the car interior. Look for openings in your car's engine and frame that might allow leaves to collect. Clean this out as best as you can. For me, I removed the wipers and lifted the cover just underneath them and did a good cleaning. I then also repaired any cracks in the cover that cuold let more water in than was necessary. I hope that will give you some benefit. One I idea I also had (Which I am not convinced Is a very good idea because of complications) was to drill drain holes into the car floor to allow any water that did collect drain away. But you have to make sure it doesn't start a rust problem or have you damage anthing underneath the flooring. Good luck.
It could be the radiator is clogged. The thermostat could be bad (prevents the coolant from circulating from radiator to engine block)
Sounds like the fuel pump is clogged.
There is a drain on the outside firewall that is clogged.
your ac might be clogged or your draining hose is clogged. its in that area
There are several things that cause overheating. The most common: Thermostat stuck in the closed position; low coolant level; water/antifreeze mix incorrect; hoses with leaks; clogged radiator; faulty water pump. Other more serious: blown head gasket; cracked cylinder head.
Sunroof drains are clogged.
Could be a clogged fuel filter, a failing fuel pump, or an intermittent fuel pump relay.
These canisters are part of a fuel vapor system that filters outflowing air from gas tank when filled. Charcoal canister get clogged or spill charcoal to fuel lines, making difficult to fill the gas tank. The charcoal canister is located behind left rear wheel, close to the bumper. They have two hoses and an electrical conector.
Possibly air conditioner drain hose is clogged
clogged drainage hole in the cowl (under the wipers)...
clogged or damaged catalytic converter
AC adds a lot of stress on your cars cooling system. I'd suspect your cooling system is sufficient to cool your car, until it needs to dissipate the extra heat from the AC. Faulty thermostat, faulty radiator fan, clogged radiator fins, bad coolant, or a faulty water pump could be some things to look into.