2004 Nissan Frontier rusty stains on driveway

I own a 2004 Nissan Frontier. It is leaving rusty looking stains on my driveway. I have taken it to a Nissan dealership twice to have this looked at. Both times they say they have no idea what’s causing this. I eventually determined it is coming from the air conditioning condensate. The AC still works fine. Do you have any idea what might be causing this and what can be done about it? Also, could you recommend a product or procedure to get these stains off my driveway?


If they say the rust is from the AC condensate drain, the moisture must be coming in contact with steel/iron.

To remove the rust stains, use something like https://www.target.com/p/clr-calcium-lime-and-rust-remover-28-oz/-/A-13821647?ref=tgt_adv_XS000000&AFID=bing_pla_df&CPNG=PLA_Grocery%2BEssentials%2BShopping&adgroup=SC_Grocery&LID=700000001230728pbs&network=s&device=c&querystring=clr%20cleaner&gclid=[GCLID]&gclsrc=ds

Or https://www.target.com/p/clr-calcium-lime-and-rust-remover-28-oz/-/A-13821647?ref=tgt_adv_XS000000&AFID=bing_pla_df&CPNG=PLA_Grocery%2BEssentials%2BShopping&adgroup=SC_Grocery&LID=700000001230728pbs&network=s&device=c&querystring=clr%20cleaner&gclid=[GCLID]&gclsrc=ds


Frame getting wet and dripping on the driveway would be my guess depending on where the stains are.

Having the drain plug cleaned out is where I’d start. If partially plugged the water that gets extracted by the AC system might be accumulating and forming rust. It’s supposed to drain out as it forms.

Mechanics use a stiff wire & compressed air , but it can be done other ways. Here’s such a u-tube link. But don’t do it the way that guy is doing; i.e. getting under the car with only a flimsy looking jack supporting. Common sense safety rules say the car needs to be supported at the very minimum by on a sturdy jack-stand.