I have an 04 AT and when I im backing up I hear a hissing noise, it seems to be coming from the front passenger side. I also hear it intermittently while driving at higher speeds. After a drive, I also smell what seems to be coolant, but I'm not sure. Any suggestions?

 

Step one..............look under your car for a puddle.
Step two..............look under hood with car running and see if you can see a leak.
Step three...........check your coolant level.......be careful here, don't burn yourself.

 

heater core ... loose cabin air filter ... behind glove box... try that?

upi may also wan check your coolant lvl or look for a green puddle

 

check ur coolant and the pass side carpet to see if it's wet!!! check coolant with cold motor if you open ur cap when hot u may be going to the hospital!!!!

 

check glove box for a snake..


beers

 

I always hear the hissing sound too. It always when I have the A/C on and it seems to come from the passenger side. Its alwasy intermidate, it becoming really annoying. There's no puddle, new radiator, coolant fine. What else could it be?