2019 Max with a failed air conditioning evaporator coil

[NukeLife]

Just FYI, was dropping my 2018 off at the dealership and ran into a guy that was dropping off his 2019 Max for an A/C problem.

He started having issues with A/C not getting cold enough a few weeks ago—the dealership didn’t find a problem.

Then a short time later he pulled his Weathertech mats out of the way and his passenger front carpet was soaked. So now they’re pulling his dashboard out to replace the evaporator.

That’s the first of these issues I’ve seen. Hopefully that’s a one-off.

I let him know about this place, if he needed to vent ( and to share his experience).

 

[Squark]

Soaked carpet is usually due to a clogged evaporator drain. The condensate backs up and spills out onto the mats. It wouldn't cool as well with all the water in there and could get musty. A failed evaporator would vent refrigerant and cause the A/C to blow warm, but it wouldn't cause water to drip on the mats. Hopefully he just misunderstood what the dealer reported.

I've always wondered if all the hot/cold cycling from the auto start-stop system would cause evaporator issues down the line. My understanding is the R-1234yf evaporators are built stronger than the R-134a ones, so hopefully it won't be a problem.

 

[NukeLife]

Ah.. that may be. He didn’t sound comfortable with the terminology so perhaps it is just a clogged drain. I should have asked if it was just water in the carpet.

I’m assuming if your entire A/C charge dumps out a pinhole leak in your evaporator, you would be able to smell it and the wet carpet would also have an oily residue.
Thankfully that’s one I haven’t experienced yet. Heater coil? Yes. And antifreeze in the carpet sux.

 

[flying68]

Soaked carpet is usually due to a clogged evaporator drain. The condensate backs up and spills out onto the mats. It wouldn't cool as well with all the water in there and could get musty. A failed evaporator would vent refrigerant and cause the A/C to blow warm, but it wouldn't cause water to drip on the mats. Hopefully he just misunderstood what the dealer reported.

I've always wondered if all the hot/cold cycling from the auto start-stop system would cause evaporator issues down the line. My understanding is the R-1234yf evaporators are built stronger than the R-134a ones, so hopefully it won't be a problem.

I don't think auto stop-start has any affect at all on the HVAC system. The engine will not shut off if the climate system is calling for the AC compressor to be on (clutch engaged). If the blower is running while in stop mode and the discharge air temp exceeds the threshold, the engine will start to reengage the AC compressor. So in reality, the system will operate the same whether auto stop-start is enabled or what. That is my observation over the last year including this summer. I don't ever turn off the auto stop-start.

 

[Squark]

I live in the south where it gets very hot and humid. Within a few seconds of the engine stopping, the air gets noticeably warmer and sticky. If I disable auto start-stop, the air stays crisp and cold the entire time. When the outdoor temps are in the 70s or low 80s, it's far less noticeable. And once you get into the mid-90s the auto start-stop system doesn't activate. It's definitely a different experience for me with and without auto start-stop, but I don't know the details on how it chooses when to stop or how long to stay stopped before restarting. I usually leave the system engaged regardless. I strongly disliked it at first, but I'm starting to come around.

 

[KSC 2019 XLT]

My 2019 Expy is having the A/C compressor and evaporator replaced under warranty. Brought it to the dealership 4 freakin times and they finally figured it out.

 

[BMW2FORD]

Check this post below if anyone has wet carpets or wants to prevent this since it’s cheap and easy and can happen to any 4th Gen. Maybe there doing the evaporator since they are worried about mold if it wasn’t draining but other than that or a Freon leak, it’s weird there replacing it if it was just from wet carpets.

Thread 'Wet front passenger carpet area. TSB 19-2345 evaporator drain upgrade.'
https://www.expeditionforum.com/thr...a-tsb-19-2345-evaporator-drain-upgrade.50029/