Terrible AC smell. Help pls

[munizfire]

Hey all.

My 2017’s AC has been smelling off (sporadically) for about a year and a half now. I’ve replaced the cabin filter a couple of times, also used 2 products I saw recommended in this forum [see pics], still no improvement.

Some comments that might be useful:
- The smell is a dusty/mildewy one.
- Just took it to get the AC checked. Freon levels were fine, and the shop had no reason to believe the Evaporator is bad.
- AC works fine, I wish it cooled more, but it cools enough.
- No apparent leaks.
- The smell gets the worst when I 'switch modes' [e.g. when going from A/C to fans (compressor off, I guess) and vice-versa; same as when switching air circulation modes too]
- Current cabin filter is a couple of months old (already ordered a new one)

Questions:
- Would something like the A/C Pro Vent and Duct Cleaner be safe to spray directly into the cabin filter duct (with the filter removed).
- Same question applies to Lysol, and Evaporator and Heater Foam Cleaner.
- Would it be a dumb idea to spray the foam cleaner directly into the AC Vents?

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[jayhoogs]

Yeah, sounds like your AC evaporator core is going out. I’m sure you’ve seen a lot about this, but it’s super common. I had mine replaced last summer on my 2017 also, and it was similar where is seemed to be working ok but I noticed a weird smell like that. Progressively got worse until the driver side vents were no longer blowing cool air. At the time I had also brought my car to one dealer where they said the AC system was working fine, but shortly after that another dealer fixed the issue. Needless to say, changing cabin air filters and spraying things in this case would not help, as it’s not actually fixing the problem.

 

[K4fxd]

Would it be a dumb idea to spray the foam cleaner directly into the AC Vents?

Don't do this. It cost me my radio and display module.

 

[munizfire]

Don't do this. It cost me my radio and display module.

Thank you for this. Lol

 

[munizfire]

Yeah, sounds like your AC evaporator core is going out. I’m sure you’ve seen a lot about this, but it’s super common. I had mine replaced last summer on my 2017 also, and it was similar where is seemed to be working ok but I noticed a weird smell like that. Progressively got worse until the driver side vents were no longer blowing cool air. At the time I had also brought my car to one dealer where they said the AC system was working fine, but shortly after that another dealer fixed the issue. Needless to say, changing cabin air filters and spraying things in this case would not help, as it’s not actually fixing the problem.

Le sigh

is this covered by a TSB?
How much did they charge you?

I was aware an evaporator replacement was something to be expected at some point, and I would probably do it myself unless the dealer doesn’t charge a whole lot.

 

[ice445]

Le sigh

is this covered by a TSB?
How much did they charge you?

I was aware an evaporator replacement was something to be expected at some point, and I would probably do it myself unless the dealer doesn’t charge a whole lot.

Most dealers quote around $2000 to do it

 

[jayhoogs]

Le sigh

is this covered by a TSB?
How much did they charge you?

I was aware an evaporator replacement was something to be expected at some point, and I would probably do it myself unless the dealer doesn’t charge a whole lot.

Stupidly enough, it’s not covered by a TSB. No idea why, because it’s obviously a design flaw being that it’s such a common issue, and that they continued using those flawed parts for several years knowing it was a problem. Luckily I had an aftermarket warranty that covered that repair, so I was only responsible for my $100 deductible, but I believe the bill showed it would’ve been around $2,200. I also prefer doing my work myself (just got done installing long tubes on my car), but being that it was covered under the warranty I had and the whole dashboard needs to come out, I just had it done by the dealer. It’s just unfortunate that the labor cost is so high, because the part itself is reasonable.

 

[munizfire]

Decided to remove the screen and radio and spray disinfectant through the vents and cabin filter cavity.

So far no smell, but I’ll know tomorrow or during the weekend. /knocks on wood

worst case scenario I’ll buy a new evaporator and take a day off to change it.

thanks guys.

 

[luca1290]

If it reappears, remove the air filter and thoroughly clean the evaporator core with an appropriate cleaning solution, yes it's safe to do so and everything will drain under the car.
Inspect visually and remove any loose debris with a vacuum cleaner before applying the solution.
Be a little gentle because the fins tend to bend.

Make sure that the drain is free and you don't have pooled water, that's a common cause of smell.

Check also the blower motor that you don't have leaves or debris that with changes in humidity release bad smell, you will have to drop the unit but usually is fairly easy.

I had a company Mercedes a few years ago that was used by a very dirty and gross colleague before me. Never knew him personally but his presence was noticeable even after the car was supposedly professionally cleaned.
Had to dismantle and clean the whole AC to get rid of the smell, every time an actuator motor was moving a flap in the system any kind of smell was coming outside.

Needless to say I lasted two weeks in the company (not for the car) and never looked back again being an employee, for anybody.

 

[Jstang23]

Decided to remove the screen and radio and spray disinfectant through the vents and cabin filter cavity.

So far no smell, but I’ll know tomorrow or during the weekend. /knocks on wood

worst case scenario I’ll buy a new evaporator and take a day off to change it.

thanks guys.

Hey, I used to work as a service advisor and what we used to clean/odorize the a/c system was stuff called Ozium. We drained the freon, put this stuff in the system, ran it for a bit, then replaced it with clean freon.

https://www.amazon.com/Ozium-Oz-San...mbsSzOCECF-FuISDfnlKHbOrt1X5z8fAaAsglEALw_wcB

I'm sure there are other ways to get it in the system, but this stuff works like a champ!

 

[munizfire]

If it reappears, remove the air filter and thoroughly clean the evaporator core with an appropriate cleaning solution, yes it's safe to do so and everything will drain under the car.
Inspect visually and remove any loose debris with a vacuum cleaner before applying the solution.
Be a little gentle because the fins tend to bend.

Make sure that the drain is free and you don't have pooled water, that's a common cause of smell.

Check also the blower motor that you don't have leaves or debris that with changes in humidity release bad smell, you will have to drop the unit but usually is fairly easy.

I had a company Mercedes a few years ago that was used by a very dirty and gross colleague before me. Never knew him personally but his presence was noticeable even after the car was supposedly professionally cleaned.
Had to dismantle and clean the whole AC to get rid of the smell, every time an actuator motor was moving a flap in the system any kind of smell was coming outside.

Needless to say I lasted two weeks in the company (not for the car) and never looked back again being an employee, for anybody.

you see, in my mind, if I’m already going through the hassle of getting all the way in, where I can visually inspect the Evaporator, might as well just replace it, knowing it’s a common failure in these cars. But thanks, if it comes down to that, I’ll also check the blower motor.

 

[Mike Pfeifer]

If it reappears, remove the air filter and thoroughly clean the evaporator core with an appropriate cleaning solution, yes it's safe to do so and everything will drain under the car.
Inspect visually and remove any loose debris with a vacuum cleaner before applying the solution.
Be a little gentle because the fins tend to bend.

Make sure that the drain is free and you don't have pooled water, that's a common cause of smell.

Check also the blower motor that you don't have leaves or debris that with changes in humidity release bad smell, you will have to drop the unit but usually is fairly easy.

I had a company Mercedes a few years ago that was used by a very dirty and gross colleague before me. Never knew him personally but his presence was noticeable even after the car was supposedly professionally cleaned.
Had to dismantle and clean the whole AC to get rid of the smell, every time an actuator motor was moving a flap in the system any kind of smell was coming outside.

Needless to say I lasted two weeks in the company (not for the car) and never looked back again being an employee, for anybody.

Can you get to the evaporator to clean it through the cabin filter opening?

 

[PoCoBob]

Decided to remove the screen and radio and spray disinfectant through the vents and cabin filter cavity.

So far no smell, but I’ll know tomorrow or during the weekend. /knocks on wood

worst case scenario I’ll buy a new evaporator and take a day off to change it.

thanks guys.

Holy Moly! The old school way of doing this would be take out the cabin filter and put the door back on to seal the system. Then turn the a/c on as cold as it goes, set the vents so air is flowing through every vent. Then go outside the car and spray Lysol or similar through the air vents at the base of the windshield. On the Mustang those vents are under the back edge of the hood so you'd have to open the hood to spray into them. Then let the car sit overnight with the Lysol in the system for as long as possible. That has always worked for me, but the car does smell like a hospital for a few days. Good luck.

 

[Andy13186]

If you use the recycling setting on ac (internal cabin air recooled) you need to turn it to non recycled air for like 4 mins before parking the car or the system just condensates and gets moldy.

 

[munizfire]

If you use the recycling setting on ac (internal cabin air recooled) you need to turn it to non recycled air for like 4 mins before parking the car or the system just condensates and gets moldy.

I do this almost every time, but unfortunately I started after the smell started.

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