9 month old P3D+. Started noticing that when I first start up the car and the A/C comes on, I'm getting a very distinct vinegar-like odor coming from the ventilation system. Puzzled me for several days, couldn't figure out what it might be.
I know a lot of cars sometimes have a mold problem in the ventilation system and it can end up with a musty smell. But this odor isn't musty, it's acrid/acidic. And the car seems to be too new to be getting a mold problem.
I thought at first it could be a refrigerant leak, but I dismissed this idea as everything I read said that refrigerant smells sweet. But, come to find out all of those write-ups were talking about older HCFC refrigerants like R-12 that have long since been phased out. Most cars since the late 90's / early 2000's have used R-134a refrigerant instead, which has a very faint ether-like odor, if any at all.
However, in 2018, the automotive industry adopted a new refrigerant with even lower global warming potential called R-1234yf, also known as HFO-1234yf. The chemical used is 2,3,3,3-Tetrafluoropropene. When 2,3,3,3-Tetrafluoropropene is exposed to air, it decomposes into several chemicals, but one of the major decomposition products is Trifluoroacetic acid, which (surprise) smells like vinegar (acetic acid). In fact, it's the same atomic structure as vinegar, but with 3 hydrogens replaced with 3 fluorines.
My theory is that I have a tiny slow leak in the evaporator coil, and when the vehicle is sitting, refrigerant gas is slowly leaking into the ventilation duct, collecting there, and decomposing to trifluoroacetic acid. When the vehicle is started up and the fan starts, the trifluoroacetic acid is blown into the cabin, creating the vinegar smell. As the trifluoroacetic acid clears the car, the smell goes away and the leak rate is so low that you can't smell it any more until the next time the vehicle is stopped and the gas is allowed to collect again.
I'm also starting to notice that I'm getting hissing and gurgling sounds from the dash on startup, an indication that the refrigerant level is decreasing in the system.
Anyone have any experience with the new R-1234yf refrigerant and has seen or heard of this before? As this refrigerant only came into use last year, any internet mentions of it are scarce.
I know a lot of cars sometimes have a mold problem in the ventilation system and it can end up with a musty smell. But this odor isn't musty, it's acrid/acidic. And the car seems to be too new to be getting a mold problem.
I thought at first it could be a refrigerant leak, but I dismissed this idea as everything I read said that refrigerant smells sweet. But, come to find out all of those write-ups were talking about older HCFC refrigerants like R-12 that have long since been phased out. Most cars since the late 90's / early 2000's have used R-134a refrigerant instead, which has a very faint ether-like odor, if any at all.
However, in 2018, the automotive industry adopted a new refrigerant with even lower global warming potential called R-1234yf, also known as HFO-1234yf. The chemical used is 2,3,3,3-Tetrafluoropropene. When 2,3,3,3-Tetrafluoropropene is exposed to air, it decomposes into several chemicals, but one of the major decomposition products is Trifluoroacetic acid, which (surprise) smells like vinegar (acetic acid). In fact, it's the same atomic structure as vinegar, but with 3 hydrogens replaced with 3 fluorines.
My theory is that I have a tiny slow leak in the evaporator coil, and when the vehicle is sitting, refrigerant gas is slowly leaking into the ventilation duct, collecting there, and decomposing to trifluoroacetic acid. When the vehicle is started up and the fan starts, the trifluoroacetic acid is blown into the cabin, creating the vinegar smell. As the trifluoroacetic acid clears the car, the smell goes away and the leak rate is so low that you can't smell it any more until the next time the vehicle is stopped and the gas is allowed to collect again.
I'm also starting to notice that I'm getting hissing and gurgling sounds from the dash on startup, an indication that the refrigerant level is decreasing in the system.
Anyone have any experience with the new R-1234yf refrigerant and has seen or heard of this before? As this refrigerant only came into use last year, any internet mentions of it are scarce.
