Toxic Fumes Coming thru Vents W/ AC On?

5literPwr

Founding Member
Jul 17, 2002
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I have a 2003 GT and would like to know what would be a likely cause of having an odor very similar to piss blowing thru my vents while I have my AC running? A quick web search revealed (not from a reliable source) that burning freon produces an ammonia-like odor which supposedly can occur when an AC system is starting to fail. What worries me is that this source claims this produces a deadly toxic fume. If anyone has any experience with this type of issue, or knows about air conditioning & refrigeration , please let me know if this is a possibility. Thanks.
 
What Causes Freon To Burn?

I researched the causes for why there is a strong odor of urine coming from my a/c vents and discovered that burning freon smells nearly identical to urine. My question is, what causes a burning of freon in the a/c system, and is there a simple fix or do I need to have a qualified person to handle the issue. Thanks in advance. Car is a 2003 GT.
 
To be honest, I don't know how freon can burn in an automotive a/c system. Freon boils and evaporates when it hits air. Leaves a smell, but as far is it burning, never heard of it. Not saying its not possible. If you have a strong urine smell, I would say check your pants. :rlaugh: Sorry, had to do it. But seriosly, r-134a has a distinct smell, and if you smell it in your car, I would suspect a leaking evaporator. Have you noticed a lack of cooling in your car? If so, I'd say you have a leaking evaporator. If you're going to tackle the fix yourself, take the car somewhere to have the refrigerant evacuated, and take it back to the same place to have it charged. DO NOT buy the junk r134a in the can at pep boys or wal mart or any of those places. They contain sealants that WILL do damage.
 
Freon (R-12) hasn't been used in a Mustang since 1993. Both R-12 and R-134a aren't flammable, unless they came out of the system in gas form with the oil charge still inside of them. You'd need them to come out basically as though a line burst wide open for that to happen though. Honestly, you probably have a mold issue in the system, especially if your AC still works. If it was leaking at a rate that you could smell it, you'd have no refrigerant left after a few minutes.
 
Maybe someone peed in your cowell vents. Who did you piss off? Start the car, turn your ac on regular, not max, roll the windows up, and spray some febreeze in the cowell vents. It will make your car smell a lot fresher. I do it whenever I detail my interior, it really makes it smell new again.
 
Freon is non-flammable and non-corrosive. Furthermore, freon is kept in a completely enclosed system, if there were a leak, all the freon in your system would discharge completely and immediately. Your problem has nothing to do with freon.
 
+1 on the "who did you piss off" comment - you're lucky they didn't cram turds into your a/c and engine intake, as I've seen that one too. Also, check the engine bay for rodents or rodent droppings. Rodern urine (I know from hamsters back in the day) is the most potent urine-like smell I've ever come across. 1 drop smells worse than a whole-festering-multi-day-unflushed toiletbowl full of human piss.
 
Yea, I did double post this topic, sorry about that. It may actually be just mold as I just bought the car and the last owner didnt drive it for a year or so before eventually selling it. I'm glad to hear that its most likely not burning freon or anything toxic. I will try the febreeze idea. Thanks to all for the help, I appreciate it.
 
For freon to be converted to phosgene it must be subject to heat of at least 400*F or preferably an open flame. Phosgene was a WW I nerve gas and supposedly it has a sweet smell. Not your problem.



He's right, and you would be very sick if you were inhaling that.
If the smell of the R134a was so strong, it would have all leaked out by now and you wouldn't have working A/C.