What's that AC smell?
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Rat Balls
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Joined: Dec 2011
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From: Scottsdale AZ, USA
What's that AC smell?
When my AC comes on there is a funky smell. Not a dead rat smell, more of a musk...and very hard to describe. Very noticeable at start up but never really goes away.
I recall my wife's MB had the same odor from the AC system and I recall someone relating it to the undercarriage coating (cosmoline maybe?). Did not have this issue with my last PCar.
Has anyone experienced the same thing?
I recall my wife's MB had the same odor from the AC system and I recall someone relating it to the undercarriage coating (cosmoline maybe?). Did not have this issue with my last PCar.
Has anyone experienced the same thing?
Race Director
Joined: Sep 2006
Posts: 19,035
Likes: 269
From: Bentonville, AR
In some cases the A/C system can develop a smell that arises from mold/mildew taking root (so to speak) on the evaporator. When the A/C is on this accumulates water from moisture condensing out of the air and when the car is stopped and the engine shut off this moisture is a good breeding ground for mold/mildew.
However, this is more likely to occur in high humidity areas. A counter to this is to try to shut off the A/C compressor a couple of minutes before reaching the last destination for the day to let system continue to run, blow air through the system, to dry this evaporator to make it less hospitable to mold/mildew.
Once this stuff takes hold it can be a pain to remove.
However, I note you are in AZ which generally has a pretty dry climate.
What then is probably going on in your car's case is the cabin air filter needs to be replaced. Over time these can develop a funky smell that is more noticeable when the A/C system is first turned on.
You can replace the filter with the activated charcoal one or the plain one. Dealers no longer carry the plain filter though (IIRC) the plain one might be available from other sources (mail order perhaps).
I just use the activated charcoal filter in my cars.
While you are changing the filter be sure to inspect the body water drains ahead of the windshield under the plastic panels on either side of the battery which is itself covered by a panel for any signs of water accumulation.
Last but not least, in some cases a drain can become blocked and water can collect in the basins. If it doesn't overflow into the cabin -- the usual sign there's a problem in this area -- it can account for the funky smell you report.
However, this is more likely to occur in high humidity areas. A counter to this is to try to shut off the A/C compressor a couple of minutes before reaching the last destination for the day to let system continue to run, blow air through the system, to dry this evaporator to make it less hospitable to mold/mildew.
Once this stuff takes hold it can be a pain to remove.
However, I note you are in AZ which generally has a pretty dry climate.
What then is probably going on in your car's case is the cabin air filter needs to be replaced. Over time these can develop a funky smell that is more noticeable when the A/C system is first turned on.
You can replace the filter with the activated charcoal one or the plain one. Dealers no longer carry the plain filter though (IIRC) the plain one might be available from other sources (mail order perhaps).
I just use the activated charcoal filter in my cars.
While you are changing the filter be sure to inspect the body water drains ahead of the windshield under the plastic panels on either side of the battery which is itself covered by a panel for any signs of water accumulation.
Last but not least, in some cases a drain can become blocked and water can collect in the basins. If it doesn't overflow into the cabin -- the usual sign there's a problem in this area -- it can account for the funky smell you report.
Race Director
Joined: Sep 2006
Posts: 19,035
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From: Bentonville, AR
Well, while I hate to throw parts at a problem I think a reasonable action would be to replace the cabin filter.
If this doesn't help then you have a pretty good idea that you will have to look further/deeper. This means more money but you at least know it is warranted.
However, before you replace the cabin air filter check the water drain basins for any signs of trash build up and that water is being accumulated. Even if there is no water any trash in these basins can account for the smell as this will get wet.
I note you have a Cabriolet, thus there might be water drains/basins at the rear of the car. (There are on my 02 Boxster, if that has any bearing.)
These drains -- if they exist of course -- should be id'd in the owners manual. While these drains probably do not account for the smell you want to be sure they are kept free of trash and water doesn't collect but instead flows down and out under the car.
If you find any trash carefully clean it out and be sure the drains are flowing freely then carefully flush the basins/drains with water.
Then see if the smell goes away. Give it a day or two and several uses of the car as there might be some lingering odor but this will diminish, should diminish. If it doesn't... cabin air filter or possibly that mold/mildew thing.
If this doesn't help then you have a pretty good idea that you will have to look further/deeper. This means more money but you at least know it is warranted.
However, before you replace the cabin air filter check the water drain basins for any signs of trash build up and that water is being accumulated. Even if there is no water any trash in these basins can account for the smell as this will get wet.
I note you have a Cabriolet, thus there might be water drains/basins at the rear of the car. (There are on my 02 Boxster, if that has any bearing.)
These drains -- if they exist of course -- should be id'd in the owners manual. While these drains probably do not account for the smell you want to be sure they are kept free of trash and water doesn't collect but instead flows down and out under the car.
If you find any trash carefully clean it out and be sure the drains are flowing freely then carefully flush the basins/drains with water.
Then see if the smell goes away. Give it a day or two and several uses of the car as there might be some lingering odor but this will diminish, should diminish. If it doesn't... cabin air filter or possibly that mold/mildew thing.
Race Car
Joined: Nov 2013
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From: Austin, TX
I had a 2001 model pickup truck I wasn't using much and each time you turned on the A/C there was a strong musty smell. Before putting it up for sale and having buyers be put off by it, I picked up a can of Zep Odor eliminator at Home Depot. Much to my surprise it worked very well!
I put the A/C blower on full blast and sprayed about half the can into the A/C intake with the cabin filter removed, spraying just a bit at a time trying to make sure I didn't soak or drown something like the A/C motor. I sprayed the rest in various A/C vents with the A/C turned off.
I don't know whether this would be safe for your Porsche, that would be your call, but I had good luck with the pickup. Of course, I was only risking a $6,000 truck, not a car so I was willing to gamble.
I put the A/C blower on full blast and sprayed about half the can into the A/C intake with the cabin filter removed, spraying just a bit at a time trying to make sure I didn't soak or drown something like the A/C motor. I sprayed the rest in various A/C vents with the A/C turned off.
I don't know whether this would be safe for your Porsche, that would be your call, but I had good luck with the pickup. Of course, I was only risking a $6,000 truck, not a car so I was willing to gamble.
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Race Director
Joined: Sep 2006
Posts: 19,035
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From: Bentonville, AR
The few times a funky odor appeared a cabin air filter change fixed it right up.
So, I have no direct experience as to what this process entails, its cost, etc.
But I would take this approach I think if the cabin air filter change didn't help and if the drains/basins proved to be clear/clean.
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Pro
Joined: Jun 2010
Posts: 605
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From: Placentia, Ca
It's called Dirty Sock Syndrome in HVAC Industry. In homes it's related to the environment in the home based on Chemicals, Paint, Food and anything thing else that is in the home. As to a car as stated changed the filter but in some cases nothing you do will get rid of it completely. I am a rep for a line of coils in the Western Region and we get this call too often and they blame us while once again it's an environmental issue.
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Rat Balls
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From: Scottsdale AZ, USA
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From: redmond wa
Site is back up.....
What helped me a LOT, '92 LS400, was/is leaving the windows down slightly in the garage each and every night. As the CHILLED, ~33F, evaporator warms some of the evaporating moisture flows out he open windows.
2001 C4 wasn't quite as bad as the Lexus, mostly odor rather than fogged up windshield within 3-4 miles EVERY coolish morning post previous day's A/C use. Oh, and learned to keep the compressor OFF unless actual cooling, initial cooldown was/is required.
Simple on/off switch in line with the compressor clutch, back of console glove box in the C4.
What helped me a LOT, '92 LS400, was/is leaving the windows down slightly in the garage each and every night. As the CHILLED, ~33F, evaporator warms some of the evaporating moisture flows out he open windows.
2001 C4 wasn't quite as bad as the Lexus, mostly odor rather than fogged up windshield within 3-4 miles EVERY coolish morning post previous day's A/C use. Oh, and learned to keep the compressor OFF unless actual cooling, initial cooldown was/is required.
Simple on/off switch in line with the compressor clutch, back of console glove box in the C4.
Pro
Joined: Jun 2013
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From: Canada, GTA
<<<@!1!@>>>
Looks like a good video how to do it:
Exactly what filter do you use ? Where do you get it ?
This thread helped:
https://rennlist.com/forums/997-foru...d-997-2-a.html
specifically this post.
Looks like a good video how to do it:
Exactly what filter do you use ? Where do you get it ?
This thread helped:
https://rennlist.com/forums/997-foru...d-997-2-a.html
specifically this post.