HVAC AC Smell on 4th Gens?

[RABAYL01]

I have that occasionally on my 22 Timberline. I live in AZ and its dry so one would think otherwise but only a few times recently I have smelled it and knew 100% what it was. My old BMW was notorious for gathering mildew even in AZ and I would have to flush it with cleaner monthly.
Did not like the fact I was smelling it in the New Expy after 7 months. So far its only been a few times so time will tell.

So your 22 Timberline is not under the scope of the TSBs. I wonder what changed during mid cycle refresh. Can you take a picture of your front AC drain tube? Thanks

 

[RABAYL01]

I checked my 2019 XLT to see if mine was missing the 90° nipple coming off the the drain for the A/C against the firewall. Mine was not installed during the build date of 11/19. Surely creating in my opinion that condensating water in being forced not to drain properly and settling in the plenum creating 2 issues. Water being drained into the RS of vehicle and also creating a foul smell when the A/C is used. It seems to me that the drain without that directional 90° the hot air from the engine is being forced back into that small opening affecting the water into the cab along with the water not draining properly creating that foul smell when first the air is used. I have inquired about the TSB through my ford dealership to see if they would cover this part. I have 40k on mine and this fix would fall under the TSB Guide for repair procedure. I have the smell when I turn on the air but fortunately haven't had any water leaking into the cabin and wetting under the carpet. I will have this done either by ford buying it or paying for it on my own. Just my take on this matter.

I bought the part through Amazon for $18. Oddly enough, you can buy it directly from Ford Parts.

 

[sjwhiteley]

Just put the elbow on mine. The carpet was slightly wet; not enough to rip it up and dry it manually. Left the mat out so the spring/summer heat should evaporate what remains.

Not a bad job. The padding behind the fabric wheel well was wet (it’s fairly exposed if you run through puddles). Jacked up the front passenger side and removed several trim bolts to pull the wheel well liner back and reach in to the drain. I trimmed the two ‘tabs’ off the bottom of the drain pipe to get the rubber angle on. It’s a bit tight to get a clamp on it so just followed the TSB. An additional liner on the firewall was pulled back to tape the hose to the firewall.

 

[3rd Expyowner123]

Never been an issue on my 2018 Expedition. Live in Deep South Texas, A/C is needed for cooling year round and common to have high outdoor humidity.

 

[Richard p Bunger]

Hey all, I have a 2019 Expedition Limited and I have had some issues with the HVAC smelling musty right after when the truck had AC on. I've tried the disinfectant method on to the HVAC intake through the cowl but it comes back eventually.

Upon further review, it looks like F-150s and super duties also have the same issue to due to poor design on the AC Drain through the firewall. The fix is a rubber elbow (looks like a PCV valve elbow) as seen in this video

2019 F-150 Wet Floor Repair

www.youtube.com

I have ordered the "Ford part" as noted through Amazon for $18 and I am currently waiting for it to try out if this is the right fix. I am just curious if others out there in the Expy/Navigator world have had the same issues.

Check you passenger side front carpet actually under the carpet the padding I bet it is wet. Mine was!

 

[Bmac1955]

Sorry for wrong production date on my Expedition. It was 10/18 for my 2019 XLT. Had the elbow for the A/C drain hose installed under TSB and that rectified the issue of the mildew smell.

 

[TX-EXPMAX]

So adding the elbow fixes the issue of water not draining out, but what's the solution if you've already got the smell in there? Has anyone tried spraying a can of evaporator coil cleaner in the drain hole, like this: https://www.lubegard.com/products/evap/

I've done this on an older F250 and it really helped clean it up, but no idea if this is a simlar setup.

 

[Password]

1. Where at the cowl vent does the cleaning spray go into?
2. I'm getting an ammonia smell from my vents, is that the typical smell? It's like a cat pee'd in the cowl vent or something.

 

[Fastcar]

Have the same issue every so often. Run the heat full bore for about 20 minutes. That should dry the box out.
On the coast of FL the air is so damn humid you have to use the heat.

 

[JimBob77]

I have a 2019 Expedition Platinum. My AC has a musty/vinegar smell every time vehicle has sat for a few hours. Tried running only the fans the last 5 mins of each ride and also running heater to dry it out, but that’s not fixing it. Floor board is completely dry - I checked under the carpet and saw no signs of moisture. Besides the elbow, has anyone identified a different root cause and solution?