Have you ever experienced sometimes driving on the highway warm air from underneath? When the AC on is OK but sometimes I like to drive with my windows down. What could it be?

 

It's normal.

 

lots of cars are doing it now. the point is to circulate outside air to prevent air from getting stagnant. cars used to have a valve that closes off the vents that suck up the outside air. because they remain open all the time, the air pressure seeps in and thats where your getting your warm air.

 

thanks, its great for winter time but it sucks for the summer...oh well

 

Yeah the air seepage through the ducts on this car is terrible. I can't even drive around in the summertime with the windows down...it feels like the heater is blowing on me.

 

Hot by the feet always meant clogged cat but maybe it's just older cars. Are you getting any rotten egg smell?

 

2007 Maxima 43k...hot by the feet (no rotten eggs smell) and I hope is not the cat and hope that it is what the other fellow members are saying...its normal

 

It's not normal or I would have the same issue, I don't.