Vinegar smell coming from AC Vents

ron1004 said:

Did it start immediately after the new AC compressor and evaporator was installed, or some time later?

If immediately after it could be that they used some kind of silicone sealant during the assembly, and would fade away soon.

If you use it constantly in re-circulation mode it's prone to grow fungus/algae.

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ron1004 said:

Do you use it constantly in re-circulation mode?

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ron1004 said:

That usually leads to mildew build-up on the evaporator, so good practice to turn it off for some times.

It could also be that the condensate drain is blocked.

Why does my A/C blow foul smelling air when it first turns on?

Most of the time when I first turn on the A/C in our 2008 Toyota Sienna, the air that blows out has a very distinct chemical - nasty smell. After a while it seems to go away. I'm not sure if I just...

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Lou O. said:

Okay, Now that we know you drive around in recirculation mode stop the habit.
Switch over to flow thru vent. Follow my Lysol procedure as described above and repeat weekly for one month. Report back to us in 4 weeks letting us know what occurred.
Thanks!

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SoCalTiger13 said:

Yeah, as others have confirmed, this is definitely caused by constantly running your system on recirc because it allows bacterial to grow. Whenever I get in someone else's car and I notice the smell, they always have the recirc permanently turned on. Those same people will also sometimes turn the system off entirely b/c of the smell or set the fan at the lowest setting which also makes it stagnate. For this reason, I never use recirc unless it is really necessary and my cars never get that smell.

Fortunately, it is relatively cool where you are this time of year. I would recommend also running fresh air with the A/C turned OFF entirely at a higher speed (doesn't need to be max speed, but close to it). This will also help speed up getting rid of the smell. Even if you don't bother to use Lysol, if you constantly run fresh air with no A/C, it will eventually get rid of the smell but will just take more time.

One last tip - when you do use A/C, at the end of your trip, I also recommend turning off A/C and just blasting fresh air at full speed through the system for about 30 seconds before you turn your car off. This will also help purge some of the moisture out of the system at the end.

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