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Discussion Starter · #1 ·
I have a 2018 SV that I have owned since new, now at 37,000 miles and replaced the cabin air filter at 25,000 miles.
In just the last couple of weeks, since it finally got cold in Colorado, I get a nasty smell out of the air vents when ever I head out with the heat on. The smell goes away after about 30 minute of driving.

I have checked the air intake under the hood below the wipers. I also pulled the cabin air filter to replace it again. Both were clear and no smell from the old filter. I also look for signs of animals under the hood. The car is always in the garage and never left outside for more than a few hours a week. We also very seldom eat anything in the car.

I do notice from time to time the car will retain the smell of carry out food for a couple of days. Sometime have to put the windows down overnight to get rid of the smell. Especially after bringing home a pizza.

I wonder if it could be the heater core? I wouldn't think so with the mileage. No loss of antifreeze.

I am going to try driving around for a few days without the cabin air filter. I ordered a new Fram one with baking soda in it. I assume no filter for a few days shouldn't be an issue? This is the first car I have ever owned with one.

It is hard to describe the smell. Just bad like something died in there, but no smell until the heat starts blowing. I have never noticed the smell with A/C running. It is not the dusty smell you get when you turn on the heat after several months.

I do have the same issue others have mentioned with very little heat output to the floor vents. Another reason I want to try running awhile without the cabin filter.

Anyway, I will report back after running without the cabin filter for a few days.

Any other suggestions welcome.
 

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It is hard to describe the smell. Just bad like something died in there, but no smell until the heat starts blowing. I have never noticed the smell with A/C running. It is not the dusty smell you get when you turn on the heat after several months.

I do have the same issue others have mentioned with very little heat output to the floor vents. Another reason I want to try running awhile without the cabin filter.
Maybe something is dead somewhere in the ducting. Maybe a piece of cheesburger fell into the defrost grate and is decomposing.

FYI, my 2021 has great heat at the floor vents. I've never checked it out, but I wonder if there's a way to close the floor ducting for the back seats? I actually have things under the seats on both sides, so maybe those obstructions/restrictions are helping to create more flow to the front.
 

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If it smells like something died in the air ducts, then something probably did...
 
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BTW, check to see if both front floor ducts/vents are providing the same amount of heat. If it's just one side that's weak, perhaps a mouse or chipmunk got stuck in the side and died, If you have an endoscope/snakecam, I'd send it into the ducting and the cabin filter housing openings to see what's there.
 

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Discussion Starter · #5 ·
Here is what is strange. I removed the cabin filter yesterday. Today we went shopping with several stops and a total distance of about 15 miles with the heat on. Both my wife and I noticed there was no smell. I even cycled through the different vent settings. I mentioned before that when I removed the filter it did not smell bad, but removing it definitely made a difference. Those filters are really hard to get seated in that small space. I wonder if I didn't have it seated in the box correctly?
Anyway, the new filter came today and it is supposed to be nice tomorrow so I will replace it, but half tempted to just leave it out.
 

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A filter is not going to make the air coming out of the vents smell unless the filter itself is contaminated with something that smells.
 

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Here is what is strange. I removed the cabin filter yesterday. Today we went shopping with several stops and a total distance of about 15 miles with the heat on. Both my wife and I noticed there was no smell. I mentioned before that when I removed the filter it did not smell bad, but removing it definitely made a difference.
Perhaps a rodent got in there and urinated somewhere on the filter, and whenever the conditions were right when the heat was on (e.g. maybe there was greater moisture outside being drawn into the system) that urine would produce an odor and be more noticable. I'm sure you thoroughly checked the old filter and saw nothing wrong (or else you would have mentioned it here) but it's possible that a clear urine stain could go unnoticed, especially if within the the folds of the filter or even under the framework of it. Kind of a stretch, I know.

I'll be replacing my filter over the next few days at the 30,000mi mark. I have no odors or issues, but it's just an upkeep thing. I didn't use the HVAC system all that much since April, and I rarely use it when the roads are overly salty because I don't want to suck that powdery salt into my car (I just keep the seat warmer and heated steering wheel on a lot) so I'm guessing the filter is going to look fairly clean.
 
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I know the OP may be skeptical that he has a rodent problem, but they can remain undetected for quite some time before evidence of their presence is observed. I would suggest that he buy a few sheets of cheap glue board that one can find in the pest control section of any big box store and lay them at the edges/corners of the garage and see what he finds each day. If there are rodents running around the garage at night, they'll inevitably get trapped. Even if there isn't a rodent problem, it can be surprising what those things catch.

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I know the OP may be skeptical that he has a rodent problem, but they can remain undetected for quite some time before evidence of their presence is observed. I would suggest that he buy a few sheets of cheap glue board that one can find in the pest control section of any big box store and lay them at the edges/corners of the garage and see what he finds each day. If there are rodents running around the garage at night, they'll inevitably get trapped. Even if there isn't a rodent problem, it can be surprising what those things catch.

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Ehh, the problem with glue traps is...you gotta deal with a animal stuck to the trap -- then what do you do with it? lol

I'd stick with conventional traps baited with peanut butter, works great for me. They meet their end without my direct intervention.

I previously had tried using those poison pellets. Unfortunately, the mice thought they hit the motherload when they found the box of poison pellets...and proceeded to stash them in various places around the garage, including in the ventilation duct of my '03... It made for an unpleasant smell for a few minutes when the fan ran...
 

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Ehh, the problem with glue traps is...you gotta deal with a animal stuck to the trap -- then what do you do with it? lol

I'd stick with conventional traps baited with peanut butter, works great for me. They meet their end without my direct intervention.

I previously had tried using those poison pellets. Unfortunately, the mice thought they hit the motherload when they found the box of poison pellets...and proceeded to stash them in various places around the garage, including in the ventilation duct of my '03... It made for an unpleasant smell for a few minutes when the fan ran...
I suggested the glue traps mainly as the fastest way to find out if he has a rodent problem. If he does, he can switch to some other control method if he doesn't want to deal with rodents that are caught. Mechanical traps can be hit/miss and bait systems may take a few days before you notice something "eating" it. With glue traps, he should find out after a single night if he has a problem.
 
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Ehh, the problem with glue traps is...you gotta deal with a animal stuck to the trap -- then what do you do with it? lol

I'd stick with conventional traps baited with peanut butter, works great for me. They meet their end without my direct intervention.

I previously had tried using those poison pellets. Unfortunately, the mice thought they hit the motherload when they found the box of poison pellets...and proceeded to stash them in various places around the garage, including in the ventilation duct of my '03... It made for an unpleasant smell for a few minutes when the fan ran...
I use snap traps and glue traps in the attic and use PTZ cams up there to monitor things. A mouse on a glue trap I'll usually smack on the head will a tiny billyclub and then place everything in a bucket of water for 10 minutes before disgarding to make sure the mouse is dead. I accidentally caught a bat in a glue trap last year and its wings were pinned. I hated to have to kill it, but I felt trying to use veg oil to release it might damage its delicate wings and cripple it, so...smack.

I use the plastic rat traps made by Victory at Home Depot to control flying squirrels. After having the roof reshingled a few years ago, that Winter the attic was filled with them. Tried live traps, but they wouldn't bite, and the roof is too high and steep to access when icy to figure out how there were getting in,. A rat trap with a hazelnut in the feed tube worked very well. I caught 27 in two weeks and then there were no more. I used a screw to secure the trap to pieces of plywood so they could not scurry off with the trap to some remote area. Sadly, the snap traps aren't always a quick kill, since a few nights I'd hear a trap go off and hear the squirrel struggling and I'd turn on the camera and see it gasping for breath under the snap arm. I always got up there quickly to do them in before they suffered more. I really hated to have to resort to killing them, but during the Winter it's kind of mean to try to relocate them (and they didn't want to go into the live trap), and they can be very destructive to just ignore till Spring...not to mention they're very noisy in the walls at night.

In the Spring, I went around and tried to find how they got in and sealed every tiny area I could find. No more flyers but I still have a resident bat that sleeps in the wall in the den. At night, it exercises its wings and flaps around in the wall for awhile, the it flys around in the attic. If a bat can still get in so can a flying squirrel. Looks like more sealing to do once the warmer temps hit.
 

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Discussion Starter · #12 ·
P

I didn't use the HVAC system all that much since April, and I rarely use it when the roads are overly salty because I don't want to suck that powdery salt into my car (I just keep the seat warmer and heated steering wheel on a lot) so I'm guessing the filter is going to look fairly clean.
What you just said might be the problem??
We recently got snow and the roads were treated. The car got filthy and I washed it. I noticed the smell a couple days after washing it and another snow storm. I wonder if the road chemicals washed into the intake and caused the smell?
 

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What you just said might be the problem??
We recently got snow and the roads were treated. The car got filthy and I washed it. I noticed the smell a couple days after washing it and another snow storm. I wonder if the road chemicals washed into the intake and caused the smell?
Tell you what....whatever my 2021 washer fluid tank was filled with upon delivery smelled 100% like rancid urine in the car whenever I used it and the heat was on....mostly this fall before the roads were salted. Do you recall using any wiper fluid while driving that possibly caused the odor?
 

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I use snap traps and glue traps in the attic and I have ptz cams that I use to monitor everything. A mouse on a glue trap I'll usually smack on the head will a tiny billyclub and then I place the glue trap in a bucket of water for 10 minutes before disgarding just to make sure the mouse is dead. Caught a bat in a glue trap last year and it's wings were pinned. Hated to have to kill it but I felt using the veg oil method on such delicate wings might cripple it so...smack.

I use the plastic rat traps made by victory at home depot to control flying squirrels. After having the roof redone the next winter the attic was filled with them. Tried live traps...no good. Roof is too high and steep to go onto when icy...so rat trap with a hazelnut in the feed tube worked very well. Snapped 27 in two weeks and then there were no more. I used a screw to secure the trap to pieces of plywood so they could not scurry off with the trap to some remote area. Really hated to have to resort to killing them but it's winter and they can be very destructive.

In the spring I went around and tried to find how they got in and sealed every tiny area I could find. No more flyers but I still have a resident bat that sleeps in the wall in the den. If a bat can still get in so can a flyer... Looks like more sealing come spring.
You're missing out on a golden opportunity. You should keep the animals around and charge admission to your attic so people can see the bats and flying squirrels--maybe even start a circus. :p:coffee:
 

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Discussion Starter · #15 ·
Tell you what....whatever my 2021 washer fluid tank was filled with upon delivery smelled 100% like rancid urine in the car whenever I used it and the heat was on....mostly this fall before the roads were salted. Do you recall using any wiper fluid while driving that possibly caused the odor?
Yes, I did use wiper fluid. Starting to think that the road crap (mag chloride?) car wash chemicals and maybe wiper fluid made a stinky mixture that stayed until things dried out.
 

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Yes, I did use wiper fluid. Starting to think that the road crap (mag chloride?) car wash chemicals and maybe wiper fluid made a stinky mixture that stayed until things dried out.
My 2003 never had outside smells coming into the car the way this 2021 does. It's almost instantaneous that the smell of washer fluid permeates the cabin as soon as washer fluid is used. I can hear that the compressor is always on for heat and A/C, so I'm guessing it's simply more efficient and better at providing air through the system than the 2003.

And now a brief intermission...
 

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My 2003 never had outside smells coming into the car the way this 2021 does. It's almost instantaneous that the smell of washer fluid permeates the cabin as soon as washer fluid is used. I can hear that the compressor is always on for heat and A/C, so I'm guessing it's simply more efficient and better at providing air through the system than the 2003.

And now a brief intermission...
 

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I have a 2018 SV that I have owned since new, now at 37,000 miles and replaced the cabin air filter at 25,000 miles.
In just the last couple of weeks, since it finally got cold in Colorado, I get a nasty smell out of the air vents when ever I head out with the heat on. The smell goes away after about 30 minute of driving.

I have checked the air intake under the hood below the wipers. I also pulled the cabin air filter to replace it again. Both were clear and no smell from the old filter. I also look for signs of animals under the hood. The car is always in the garage and never left outside for more than a few hours a week. We also very seldom eat anything in the car.

I do notice from time to time the car will retain the smell of carry out food for a couple of days. Sometime have to put the windows down overnight to get rid of the smell. Especially after bringing home a pizza.

I wonder if it could be the heater core? I wouldn't think so with the mileage. No loss of antifreeze.

I am going to try driving around for a few days without the cabin air filter. I ordered a new Fram one with baking soda in it. I assume no filter for a few days shouldn't be an issue? This is the first car I have ever owned with one.

It is hard to describe the smell. Just bad like something died in there, but no smell until the heat starts blowing. I have never noticed the smell with A/C running. It is not the dusty smell you get when you turn on the heat after several months.

I do have the same issue others have mentioned with very little heat output to the floor vents. Another reason I want to try running awhile without the cabin filter.

Anyway, I will report back after running without the cabin filter for a few days.

Any other suggestions welcome.
Now Listen up folks, this post reminds me of a situation that happened to me many years ago, back in 1990 (I think)
I had bought a new VW the previous year and It was a beauty, the car looked and "smelled" like a brand new car for at least a year. And then came along my second child, she and her older brother had been fighting in the back seat for about a hour, and I couldn't take one more minute of the kicking on the back of the driver seat......Bless those kids, cause I was about to take my belt off....well you know what I mean,....lol
Anyhow, we were on our way back from the grocery store one afternoon, when unbeknownst to me that one of those sweet little kids opened up a can of cat food and stuck it under the seat where it sat there inside the car and the high temperature of at least 98° for a few days and ut slowly started to rot in that little can of food, at first I thought the same thing, maybe something had crawled inside and died somewhere... I did everything I could think of to find the offensive oder but to no avail it was useless, the can had somehow worked its way up into a area that I could not see or feel as I so desperately tried to find. so I was never really sure of where the offending stench was coming from.....it must have been a week of the foulest oder you can imagine.....I ended up paying a professional car detailing company quite a bit of money, and after 2 hours the can was found,
So now let me tell you what the kids punishment was.....I figured that since I had to deal with the stench for days while driving to and from work, it was only fitting that both of those kids had to do the same, so I hid a little bit in a plastic cup underneath each of their beds......To this day, my grandchildren are aware that they should never open food if any kind in a car, My children taught their children well.....lol
 

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I have a 2018 SV that I have owned since new, now at 37,000 miles and replaced the cabin air filter at 25,000 miles.
In just the last couple of weeks, since it finally got cold in Colorado, I get a nasty smell out of the air vents when ever I head out with the heat on. The smell goes away after about 30 minute of driving.

I have checked the air intake under the hood below the wipers. I also pulled the cabin air filter to replace it again. Both were clear and no smell from the old filter. I also look for signs of animals under the hood. The car is always in the garage and never left outside for more than a few hours a week. We also very seldom eat anything in the car.

I do notice from time to time the car will retain the smell of carry out food for a couple of days. Sometime have to put the windows down overnight to get rid of the smell. Especially after bringing home a pizza.

I wonder if it could be the heater core? I wouldn't think so with the mileage. No loss of antifreeze.

I am going to try driving around for a few days without the cabin air filter. I ordered a new Fram one with baking soda in it. I assume no filter for a few days shouldn't be an issue? This is the first car I have ever owned with one.

It is hard to describe the smell. Just bad like something died in there, but no smell until the heat starts blowing. I have never noticed the smell with A/C running. It is not the dusty smell you get when you turn on the heat after several months.

I do have the same issue others have mentioned with very little heat output to the floor vents. Another reason I want to try running awhile without the cabin filter.

Anyway, I will report back after running without the cabin filter for a few days.

Any other suggestions welcome.
  • I had a mouse making a nest in my brand new Murano 4 months ago. I got some peppermint spray that was made to spray into the engine compartment and no more problems with mice nesting. Definitely could be something DEAD.
 
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