Jeremy Patrick

Hello folks,
Seems the general topic of smells from the HVAC has been approached multiple times, but I'm still lacking in options. Hoping you knowledgeable folks could offer a bit more insight.

2019 XTS. About 3-4 months ago started noticing some funky smells when the HVAC fan came on after vehicle startup. Come to find out the cabin air filter had never been changed since we bought the vehicle despite that being marked as 'checked' on the oil changes done.
Guess there are some things you just need to confirm yourself........... Anyway, thinking that was probably the source of all evil here, I pulled that blackened filter out and tossed it. Had a new filter ready to roll. Based on the various posts I'd seen about vinegar type of smells (to me at least) I unloaded an entire can of lysol followed by a can of ozonium into the exterior cabin air intake. At the time I had thought the smell was only on fresh air, not recirculating.

Riding high (literally) on those fumes for the next few weeks seemed like anything in the ductwork had been nuked by the lysol.
Fast forward a few weeks and the smell started to come back again. My mind started going over the other options that people had mentioned such as a clogged AC drain but after a follow up visit to the shop (NOT the same guys who did the oil changes!) they spent an hour and a half looking over things and couldn't see any sign of things clogged or otherwise out of place. Only thing they were able to find is some mouse droppings in the baffles of the cabin air filter. Just droppings through, nothing chewed up which would make me think the little pests only got into the upper areas of the ductwork. So the tech's assessment was that urine in the filter was probably causing the smell.
Fast forward again about a week and the vinegar smell is back. I already have a few products in mind from amazon from spray to a rodent deterrent device but that still won't fix the smell issue I'm currently faced with.
The one thing I never heard much about throughout the various posts on HVAC smells is how long they actually last for. For my scenario the smell seems to peak at vehicle startup but after a minute or two has diminished significantly. Pretty much to the point where after 3 minutes or so you can't smell anything. Also doesn't seem to matter if the recirculating function is on or off. And if my theory is right, when I've had multiple driving sessions in a day, the amount of time the vehicle sits does seem to correspond with how much odor there is on startup.

So what do I do now? I have a spare can of lysol and ozonium but that just seems like a 2 week bandaid. Scope the ducts? see what could possibly be lurking?
Never had this issue with other vehicles I've owned so this is a first for me but I'm determined to do what I can to resolve it. Wife is halfway along with our second child and the last thing I need is for her to get in, start the truck up and she ralphs all over the passenger side because the smell is too much for her.
Since the smell only seems to last for a few minutes, it makes me think there is water or whatever liquid collecting after turning off the vehicle, but getting blown out/evaporating as the fan kicks in. I have a USB snake scope if that method would be worth while. although I'm very visual so if there are any schematics/diagrams that show how the ductwork actually goes in the vehicle, that would help me know where I'm looking.

Any ideas/thoughts/suggestions are welcome!

Thank you

SHO4CY

What worked for me was doing an Ozone treatment with an Ozone generator. A/C on high, doors closed, no one in the cabin, for about 30-60 minutes. Then anytime you use the A/C in the future, be sure to turn the A/C off before you get to your destination, but turn the fan on high with just the vent on. Maybe about 4 blocks before you get where you are going. This seems to clear out the additional moisture that sits in the system and I have not had issues since.

Other have mentioned, but it almost appears to be a design flaw with either the condensing coil being coated properly and/or the condensate drain design not being able to drain all the moisture properly. Good luck 👍

Jeremy Patrick

Got it. So from what you are saying it is liquid collecting...
One thing I forget to mention is I'm continuing to see this even if the AC isn't cranked up to high. maybe a few clicks to the left of neutral and it still has a smell.
Would this be a flaw that no matter level of AC is being used?
Also is this a flaw that has been seen on other Ford vehicles or does it seem to be just with the F150 line?

SHO4CY

I think it's a combination of a few things potentially. If you search other threads you'll find people that have had similar issues with different makes/models of vehicles. I personally have never had this issue before though. While I agree it is annoying and no one should have do deal with a moldy musty A/C smell, at least there seems to be a decent way to avoid it. I just kick myself each time I forget to turn off the A/C before I get to my destination because sitting still with the vent on high doesn't seem to work as well as moving from my experience.

The interesting thing as well is has to have something to do with sitting for longer periods of time. When I run out for lunch and shut the truck off for a short period of time (to run in to get a sandwich for instance) I don't run the vent and when starting back up no smell issues. But letting it sit overnight can change that. For instance if I totally forget to run the vent and park the truck in the garage overnight, I can still get a brief musty smell the next morning. Do you park your truck outside overnight or is it in a garage?

Jeremy Patrick

all outside which from what I've read is part of the issue with the mice.

So when you say turn the AC off, are you just hitting the AC button and leaving the fan and temp dials as is?

52merc

This is what is often recommended.

Jeremy Patrick

Watched the video. So this looks like it’s aimed at trying do get rid of the smell is in the car, but if after a few minutes of running the fan the smell dissipates, is there any reason to actually trying to treat the smell? I’m guessing a small mark could probably still be circulating around the cabin.
I still have that bottle of Lysol and ozonium, but I’d have to figure out some way of holding that nozzle down so I have to sit in the car was it until it’s empty .

for just a daily routine though, is that where are you just turn the button for the AC off within a couple minutes of getting to your destination?In my more fuel sipping vehicles I actually didn’t run the AC much unless it was completely miserable outside. So maybe that is why I never really saw this much of an issue.
maybe a good practice I should get back into, and just leave the AC button off…..

SpencerPJ

It would be nice if Ford would integrate a fan down if AC has been running, outdoor temp above X degrees. Mine smells must on occasion, first thing in the morning.

digitaltrucker

or use a coated evap coil.

tmcolegr

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