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Weird smell from AC vents. Still unsolved. Updated with more info.
I have THE WORST luck with weird car problems. The car was under CPO when this started and the smell was verified by the dealer. They have since been giving me the runaround. PCNA is giving me the runaround. I’m out of options with them without escalating big time, so I’m taking ownership of solving this for now. This car is a really amazing spec and I want to fix this desperately.
Car is a 2014 991.1 C4S about 20k miles. PDK No mods. Everything seems to check out, both from a dealer and from an Indy.
This smell comes through the AC vents after stopping sometimes. Only when the car is hot and is strongest when doing multiple low speed stop and goes. Like stopping every block for stop signs/red lights in a neighborhood. It gets successively worse on repeat stops. The smell will start 2-3 seconds after stopping. It will go away after 5-10 seconds or as soon as I start driving.
It does not smell on the first stop after a hard drive. Or stopping after cruising on the freeway. Maybe slightly, but not enough to raise suspicion.
The smell is a dank plastic smell. Almost exactly like the inside of a Dicks Sporting Goods store. At first I though it was transmission fluid because it reminded me of ATF.
Troubleshooting: the smell is 100% coming from outside the car. It goes away completely when the ac blower is off or the system in on recirculate. I have taken apart the fresh air intake and observed the recirculate valve closing, which isolates the car right after the intake. So it has to be coming from outside.
I purchased all the fluids from the car to do oil changes. (Transmission, awd controller, clutch) and smelled them. None of them smell exactly like this smell. So at this point I don’t think it’s any of these fluids. I also smelled the engine oil, brake fluid, and coolant. None of these smell like this smell either.
Edit: Both cabin air filters replaced. Ive stuck my nose EVERYWHERE and cant smell anything.
I also drove another 2014 C4S and it did not smell. So this is unique to my car.
I wonder if your drain is clogged from the evaporator. It looks like a plastic tube hanging low under the car behind the passenger side front wheel area. See while running the A/C if its dripping condensation/moisture if its not then its building up inside the evaporator box inside the car. I have heard about issues with the A/C compressors on these cars going bad prematurely check that area out as well.
can you smell the smell if you get out of the car?
I edited for this. Yes, changed both filters. Seeing as the smell only lasts 5-10 seconds after a stop, I cant really get out and find it. I have not been able to duplicate it in a way where I can get out and check.
Originally Posted by 2-Rotor
I wonder if your drain is clogged from the evaporator. It looks like a plastic tube hanging low under the car behind the passenger side front wheel area. See while running the A/C if its dripping condensation/moisture if its not then its building up inside the evaporator box inside the car. I have heard about issues with the A/C compressors on these cars going bad prematurely check that area out as well.
Thanks for the input. From what I have read, the drain drips straight onto the under body panels and these have to be removed to access the drain. Ill be checking this out when I lift the car to change all the oils.
Try doing one of those heaterbox "flushes". We did them when I worked for Toyota. Sometimes we would get cars with that same "dank burning plastic smell" and it be remedied with the cleaning service.
It's a spray can with a tube that hooks to the drain hose. Spray the whole can, let it drain out and wait for it to finish and dry out. Have never had a return customer.
00289-ACRKT is the Toyota part number.
The little can is like febreze spray for the filter.
The smell is a dank plastic smell. Almost exactly like the inside of a Dicks Sporting Goods store. At first I though it was transmission fluid because it reminded me of ATF.
.
I was doing some reading on the Dick Sporting Goods forum and someone had just posted their local store smells like a 2014 C4S, go figure
Here's what I've used in the past. You may need a couple applications, and maybe remove the cabin filter before you spray it in. Plus let the car air out for a day or more, or put in a small fan into the open door of the cabin filter compartment to circulate the air. Those bacterial infections can be hard to eradicate in the dank dark confines of the car’s air passages.
”nextzett 96110515 Klima-Cleaner Air Conditioner Cleaner - 10 fl oz"
Try doing one of those heaterbox "flushes". We did them when I worked for Toyota. Sometimes we would get cars with that same "dank burning plastic smell" and it be remedied with the cleaning service.
It's a spray can with a tube that hooks to the drain hose. Spray the whole can, let it drain out and wait for it to finish and dry out. Have never had a return customer.
00289-ACRKT is the Toyota part number.
The little can is like febreze spray for the filter.
Can confirm that these products, even off the shelf ones from the likes of walmart, work wonderfully. Did this on a unicorn RAV4 I bought years ago with a super stanky interior, got rid of maybe 90% of the a/c condenser smells.
Smells are hard. Ive had AC mold in other cars and it was totally different. Still open to trying this though.
What really has me convinced its something else is the driving situation contribution to the problem. Why would this only happen when stopped and then only when start-stopping repeatedly if it were an AC mold issue?
agreed - to me it sounds more like a slow plastic wire getting hot since the air flow is reduced --
ie - freeway lots of air ... no smell
stop and go -- no air and you get the smell
Anyway - as you said "Smells are hard". - Good luck
A few ideas:
(1) PDK or Manual? Gear oil has a very weird smell that is kinda plasticky when hot (and kinda fishy sometimes). It doesn't usually leak though, so that would be a kind of out-there occurance.
(2) Clutches can also make weird smells - but usually only at EOL, and you'd be noticing the slippage, I would think.
(3) Does the smell occur on both standard venting and recirc? That could help isolate inside the car/outside the car.
02-22-2021, 02:36 AM
Weird smell from AC vents. Still unsolved. Updated with more info.
