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Sweet Solvent/Chemical Smell from AC (NOT mold/mildew related)

Zarlov

Member
Mar 23, 2019
5
1
Salem, VA
So I have had my M3 to the dealer twice to try and get rid of a fairly often occurring "sweet" solvent/chemical smell. I don't know exactly what ethylene-glycol smells like, but my guess is this might be it. This is NOT the mildew/mold/dirty sock smell people have had lots of issues with.

I've had my car since April this year (new with 17 miles) and it is a 2018 built in Sept. last year. It sat on a lot for many months before I purchased it. I've smelled this odor occasionally when I first got the car but I honestly thought the smell was coming from outside in the environment, like a local chemical plant. Recently the chemical odor seems to be getting stronger and staying for longer. The smell goes away when I put the car on recirculate. It only happens when pulling in fresh air with the AC.

My first trip to the SC resulted in them doing the standard AC condenser clean out and new cabin air filters... which did nothing for this smell. I just got back from my second trip today. They kept it over a day or two and said they had 6 people, including the service manager and head techs get in the car with full AC on, both inside the shop and outside when it got hot. No one could smell any odors emanating from the vents. They also did a thermal check on the AC (which, from what I understand, just checks the temp of the air coming from the vents) and visually checked for a leak. They said they can't reproduce the smell and the AC should be fine since it's cold air and they don't see any leaks.

While driving back with my family (I live 2.5 hours away from this particular SC), the smell came back after a brief rainstorm on the interstate... it was VERY strong this time. My wife smelled it and my 7 and 5 year old boys smelled it, so at least I know I'm not crazy or severely sensitive to smells. I really don't want to be breathing this in since I'm not sure what it is and it can be nauseating after 10-20 minutes. Turning on recirculate always makes it go away, but I don't think I should have to do that every time I start to smell it.

I'm probably going to try a different SC next that has a much larger volume of business. Has anyone experienced anything remotely like this and were you able to find a remedy? I'm getting desperate to get rid of this odor!

I have also tried to call one of 3 different SCs around me several times to actually talk to a technician with no luck. I can't ever reach a real person from Service. I need to actually talk with a technician who won't just say "oh, it's the standard mold/mildew AC problem... we'll just clean your condenser and replace your filters" because that's NOT the problem. All the SCs near me at at least 2.5-3 hours away.

I've also read in many other places (Tesla official forums, reddit, here) that other people have experienced the same smell that seems to go away when recirculate is on, however, there doesn't seem to be any follow-ups or fixes in these posts.

Thoughts, comments, ideas??
 

Tessaract

Member
Aug 12, 2019
337
338
Ottawa
So I have had my M3 to the dealer twice to try and get rid of a fairly often occurring "sweet" solvent/chemical smell. I don't know exactly what ethylene-glycol smells like, but my guess is this might be it. This is NOT the mildew/mold/dirty sock smell people have had lots of issues with.

I've had my car since April this year (new with 17 miles) and it is a 2018 built in Sept. last year. It sat on a lot for many months before I purchased it. I've smelled this odor occasionally when I first got the car but I honestly thought the smell was coming from outside in the environment, like a local chemical plant. Recently the chemical odor seems to be getting stronger and staying for longer. The smell goes away when I put the car on recirculate. It only happens when pulling in fresh air with the AC.

.....
Thoughts, comments, ideas??
I think you're guess that the smell is anti-freeze is correct. Although ethylene glycol and propylene glycol are supposed to be odorless, I think real world antifreeze contains additives that cause the smell. I've smelled anti-freeze before (massive leak of cooling system in previous ICE vehicle), and it does smell chemically sweet. (Ethylene glycol tastes sweet too, and has been used to artificially sweeten wine in the past, but it's unfortunately also toxic to ingest). I don't think smelling it is toxic, but I definately think there's a leak in the cooling system somewhere. Perhaps in the battery, where temperatures rise during supercharging...
 

camalaio

Active Member
May 28, 2019
1,483
2,181
Vernon, BC, Canada
There is at least one service bulletin regarding coolant leaks which applies to 2018: https://static.nhtsa.gov/odi/tsbs/2019/MC-10153432-9999.pdf

It's apparently for "Model 3 vehicles built between approximately October 8, 2018 and December 29, 2018", which may not apply in your case.

However, this is specifically for the rear drive unit. I wouldn't expect that to propagate to the front where I imagine the air intake is, especially while in motion.

In places you commonly park, do you see any blue coolant on the ground ever? There will be some water dripping from the AC unit, this is normal (just condensation).
 

CarterStC

Member
Jun 26, 2018
183
158
CA
I was driving up in the Pacific Northwest this week when it was raining. We experienced the exact same issue - it is related to moisture, but I'm not sure exactly what it is. My daughter googled it and said it was a mildew smell, but its a new one to me. The weird part was that it was intermittent. Some wet periods it was there and other times it wasn't. Also, I tried turning off the vents and fan and sometimes it would still waft in - especially if I opened the windows for a bit. The smell went away when it dried up.
 
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Zarlov

Member
Mar 23, 2019
5
1
Salem, VA
There is at least one service bulletin regarding coolant leaks which applies to 2018: https://static.nhtsa.gov/odi/tsbs/2019/MC-10153432-9999.pdf

It's apparently for "Model 3 vehicles built between approximately October 8, 2018 and December 29, 2018", which may not apply in your case.

However, this is specifically for the rear drive unit. I wouldn't expect that to propagate to the front where I imagine the air intake is, especially while in motion.

In places you commonly park, do you see any blue coolant on the ground ever? There will be some water dripping from the AC unit, this is normal (just condensation).
I do not see any coolant or other fluids on the ground. I am at the Service center right now and can’t reproduce it. They even wet the front of the car and pulled the cabin filters to smell. They also let me smell wiper fluid and the red coolant they use. The smell I have is closer to the wiper fluid solvent smell than the coolant.

I’m starting to wonder if there is a reaction between the wiper fluid or other moisture and the anti-bacterial coating on the backside of the filters?
 

Zarlov

Member
Mar 23, 2019
5
1
Salem, VA
I was driving up in the Pacific Northwest this week when it was raining. We experienced the exact same issue - it is related to moisture, but I'm not sure exactly what it is. My daughter googled it and said it was a mildew smell, but its a new one to me. The weird part was that it was intermittent. Some wet periods it was there and other times it wasn't. Also, I tried turning off the vents and fan and sometimes it would still waft in - especially if I opened the windows for a bit. The smell went away when it dried up.

Had you used your windshield wiper fluid at some point during your drive?
 

Zarlov

Member
Mar 23, 2019
5
1
Salem, VA
I only get that sweet smell when I use the wiper fluid. Man oh man that is a strong smell. Could it possibly be a wiper fluid leak?

After going to the SC yet again, I couldn't replicate the smell... of course. I did ask them if they could let me smell both the coolant and the wiper fluid, which they did. To my surprise, the coolant didn't smell like the chemical/solvent I thought it would, but the windshield fluid (which didn't smell exactly like it) was much closer to the smell than the coolant. So maybe it is wiper fluid related? But I don't normally use the wiper fluid and this smell seems to happen regardless of me using it, so you may be right that there is a leak in the wiper fluid reservoir.
 

350z

Member
May 1, 2019
32
18
Montreal
Thanks for posting on this topic. I too have recently noticed a sweet smell similar to a coolant leak. I keep thinking it’s the car in front of me, however, I now believe it might be my car, which is a 2019 Model 3. I will continue to monitor.
 

lolder

Member
Jun 11, 2016
916
825
SW Florida
I had this intermittent smell also in a July 2018 build. I live in Florida and only fill the wiper fluid with distilled water and the smell has disappeared. I think it's the residual smell of wiper fluid.
 

VikH

Supporting Member
Supporting Member
Nov 23, 2015
1,083
1,025
Midwest, USA
I have this exact problem on my 2021 MYP. I get a strong chemical smell through the A/C when it is raining outside and the car is parked outside. I will also get the smell when using the washer fluid. Something is getting exposed to moisture in the A/C system and reacting. Does anyone know the solution?
 

bwbrs

Member
Sep 9, 2020
47
27
NJ
Strange coincidence as I was thinking of this today. I got my windows tinted a month ago, I thought it could be leftover moisture from the windshield tint lube / whatever coming through the vents that may have dripped below the dash or trim. This only happens at certain elevations and temperature where my cabin is almost 'moist' but not quite that level, just a noticeably sweet smell and somewhat wet feel to my steering wheel / arm rest that goes away as soon as the AC kicks in. I don't know how I would even get a SC to replicate this.
 

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