Odor when AC is running

[vucetica]

Hi everyone!

I’m a new owner of a 2025 Expedition (Platinum). This is my first truck and so far I would say that the experience is so-so (coming from Honda Odyssey, in some regards this is a downgrade ).

Anyway, we started using AC quite a bit here in Virginia a couple of months ago (it was the first time for this car as we bought it in December). I noticed two things that might be related to each other:
- there is no the usual water leak under the car that ac systems leave when they are working in hot and humid environments.
- there is bad moldy odor when we turn the ac on (bad to the point that sometimes we just turn it off and open windows).

The car is still under warranty, of course, but we are going on a trip in a few days amd dealership (again, of course) has appointment availability in a couple of weeks.

Reading about it, it seems that drain pipe might be clogged, but looking under the car, I can’t see the thing.

Another thing: having separate climate controls in the back, I would think that there is another AC for the back that should have it’s own drain. If that is the case: I would say that it is a very small chance that both are clogged at the same time.

Anyway, does anyone known if this might be some small DIY thing or is it a job for the dealership?

 

[AWAR]

I would look at the cabin air filter. The case drain should be below where the heater hoses and air conditioning lines connect. You may need to loosen or remove the passenger front inner fender. The drain should be below the nut colored in this drawing purple. This is behind the battery and shows the PCM disconnected.

 

[dlcorbett]

Hi everyone!

I’m a new owner of a 2025 Expedition (Platinum). This is my first truck and so far I would say that the experience is so-so (coming from Honda Odyssey, in some regards this is a downgrade ).

Anyway, we started using AC quite a bit here in Virginia a couple of months ago (it was the first time for this car as we bought it in December). I noticed two things that might be related to each other:
- there is no the usual water leak under the car that ac systems leave when they are working in hot and humid environments.
- there is bad moldy odor when we turn the ac on (bad to the point that sometimes we just turn it off and open windows).

The car is still under warranty, of course, but we are going on a trip in a few days amd dealership (again, of course) has appointment availability in a couple of weeks.

Reading about it, it seems that drain pipe might be clogged, but looking under the car, I can’t see the thing.

Another thing: having separate climate controls in the back, I would think that there is another AC for the back that should have it’s own drain. If that is the case: I would say that it is a very small chance that both are clogged at the same time.

Anyway, does anyone known if this might be some small DIY thing or is it a job for the dealership?

What about it makes it a downgrade from the minivan?

 

[vucetica]

@AWAR , thank you! I'm able to see the area that the picture is showing, but you are right, I will have to remove the fender in order to access it. Will take it to the dealership as I'm not sure if any intervention with a screwdriver will affect the warranty.

@dlcorbett - Expedition is a very nice powerful car, really REALLY fun to drive. But if we compare, I could just fit more stuff in the minivan's trunk, the overall quality (for example, when I look at how the panels align and such...also, Expedition just vibrates quite a bit at around 80mph - like they didn't balance the tires well or something), the little things like the one I'm asking about (of course, problem with the odor from AC is nothing serious that gets me stranded on the road, but again, the first time we took Odyssey to the dealership/mechanic is when we decided to sell it, at 120k miles - we have 6k miles on this Expedition), and so much electronics without any buttons (our minivan was old-school...and I liked it for that...now I have a feeling that I'm spending too much time tapping on the screen declining SiriusXM subscription and "connectivity package" - whatever that means). Again, Expedition is a great car and I have no regrets...just miss a few things

 

[TKinPA]

I have the same problem with my 22 Limited. I contacted dealer and they said odors are not covered under warranty unless drain is faulty. I paid them $120 to run a can of friggie fresh thru it, that lasted a day. I just did the foam myself. Bought a can from Auto Zone and sprayed it up the drain. It is better but still there. Is the real fix to have the evaporator replaced and box disinfected? Has anyone tried this ? Did it work? What was the cost?

 

[Fastcar]

Here's a quick fix you might be interested in. Start it up, run it with the heat on high for at least 20 minutes. That may clear up the odor.

 

[TKinPA]

Thanka for the tip I'll try it..

 

[Fastcar]

You might want to run it on recirculate. With the windows up. The heat running through the car body filter should dry it out.

 

[Mr Big]

@TKinPA My GEN4 had this issue. I started the engine and put the fan on high with max heat and outside air. I went to the vent outside on the passenger side near the windshield and sprayed Lysol disinfectant into the vent. I let it run in that mode for around 15 minutes.
I was fine for a few months, but it always came back. When it did, I just repeated the process.