sour odor when new Leaf starts

Hello!

Very happy to have found this forum!

I am the proud owner of a Nissan Leaf SL+ that I purchased new on July 3, 2020. It has about 1500 miles on it now.
I am hoping someone can advise me about a peculiar problem.
For the last 2 or 3 weeks I have noticed a strong sour odor, like Vinegar, coming through the heating/cooling vents. The odor is not there when the engine is off. The car interior is perfectly fine before I start the car but as soon as I do so, the smell starts. I have sprayed the interior with a deodorant spray to make sure that it is clean and odor-free. I am wondering if there is some kind of leak in the engine or A/C area?

Thanks very much in advance for any advice and suggestions. FYI I am in Phoenix, AZ.

Condensation can form in the A/C and grow mold - especially if you use Recirculate all of the time.

Cats peeing on the windshield vent area, but I would hope not.
But it's probably A/C evaporator box related.
I do know it's been raining a lot in Virginia.

Ouch. That sucks. I recall hearing of the prob back on 350Z's as a co-worker's (WAY back then) 03 Z had that problem. Google for site:my350z.com dirty sock smell. I recall the dealer had to use Frigi-Fresh on the evaporator to help resolve it.

I'd be surprised about mold given how crazy hot and dry it is over in Phoenix but that's just me...

cwerdna said:

Ouch. That sucks. I recall hearing of the prob back on 350Z's as a co-worker's (WAY back then) 03 Z had that problem. Google for site:my350z.com dirty sock smell. I recall the dealer had to use Frigi-Fresh on the evaporator to help resolve it.

I'd be surprised about mold given how crazy hot and dry it is over in Phoenix but that's just me...

Click to expand...

Thanks very much. It cant be mold in Phoenix. Cats also not because it is in a basement garage.

will check out the my350z.com.

Have you checked the cabin filter? Perhaps something has been sucked into it?

Thanks to everyone for the advice. I just returned from the dealer (ABC NIssan, Phoenix, good service). A service manager named Nick identified the issue immediately. He explained that the problem was mold/mildew in the A/C filter, even though there are only 1570 miles on the car. The default A/C setting in the Nissan Leaf is to recirculate air. This saves energy because recirc air is already cool and needs less energy than fresh air to cool. However, this means that internal humidity from the passengers gets deposited in the filter which leads to mold/mildew. They showed me the old filter that was black with mold and it smelled sour like vinegar. The fix was to replace the filter and spray the A/C system. To avoid in future they recommended to manually turn off recirc and when in garage to leave the windows down an inch or so.

Looking at the mold-filled filter I have to agree with this explanation but I am still puzzled. I drove three kinds of Toyotas in very humid Houston for many years and never had this problem. I remember noticing that the default setting there was recirc. Also, in Phoenix I have had a Prius for much longer and this problem has not occurred. I believe the default on that is also recirc but will check.

in my last post I forgot to add that the Moderator Leftiebiker was 100% right! I I discounted her/his advice because I have never had this problem with any other car including three kinds of Toyotas (with recirculated air) in humid Houston. Must be something to do with Nissan A/C design.

Thank you Leftiebiker!

I've had this problem with several cars. I even posted a 'recipe' for a less toxic A/C system cleaner regularly on alt.autos.volvo regularly. Basically, it's vodka and apple cider vinegar (because that smells the least awful). The way to avoid this happening again is to either not use Recirculate with A/C, or to at least open the air intake and shut the A/C off at least 30 seconds before turning the car off.

sriram said:

Thanks to everyone for the advice. I just returned from the dealer (ABC NIssan, Phoenix, good service). A service manager named Nick identified the issue immediately. He explained that the problem was mold/mildew in the A/C filter, even though there are only 1570 miles on the car. The default A/C setting in the Nissan Leaf is to recirculate air. This saves energy because recirc air is already cool and needs less energy than fresh air to cool. However, this means that internal humidity from the passengers gets deposited in the filter which leads to mold/mildew. They showed me the old filter that was black with mold and it smelled sour like vinegar. The fix was to replace the filter and spray the A/C system. ...

Click to expand...

Also check to make sure the condensate drain is not blocked. I.e., there should be a tricle of water under the car when parked for a few minutes with the AC on.

I also 2nd Lefties suggestion to turn off AC for a bit and let the fan run before shutting down the car. I try to do that when I'm a minute or two from destination. It's a good practice for any vehicle to help prevent funky HVAC odors.

I also run the fan with the AC off just before shutting down the car. I treat it as 30 seconds of free AC since the evaporator stays cold for some time after the AC is off.

Also check to make sure the condensate drain is not blocked. I.e., there should be a trickle of water under the car when parked for a few minutes with the AC on.

Click to expand...

Definitely. I should have added that. I'd say that between a third and half of the time, this is the problem. Also, if you have a sunroof (not a Leaf option) check the drain line from that.

LeftieBiker said:

Condensation can form in the A/C and grow mold - especially if you use Recirculate all of the time.

Click to expand...

Bingo. The fix; turn off A/C and flip the fan to high for the last 30 seconds or so on fresh air. For me, its more like 2 minutes but in Phoenix? Guessing 30 seconds would be plenty of time. You should also change your cabin filter twice a year. I would save the old one, wash it, dry it and reuse it. They are fairly durable.

Thanks for all the advice and suggestions! But I am still puzzled why this happened in 3 months in my brand new Leaf and does not happen in my Toyota Prius and Avalon, both in Phoenix over the last 18 months and several years in Phoenix. I thought recirc is the default in these also.

I haven't had a problem with it with my two Leafs, and it isn't a commonly reported one here. Either it is something to do with your car in particular (like a blocked condensate drain hose) or it's something to do with how you in particular use the car. BTW, we had a 2010 Prius that we leased for 3 years. Insects or spiders managed to block that hose, the rugs got wet, and we had to replace all of the carpeting because mold was growing in it. The dealership wanted thousands of dollars for that - and claimed that it was a rare issue - so we had exact fit aftermarket carpet installed, for about a Grand.

One difference is that there is no engine heat on a Leaf. Even the Prius I would assume generates quite a bit of heat from the engine when it runs. Maybe that was enough to dry out the AC system or maybe it's just how the Leaf's AC is constructed. Or maybe something was odd with your car, this is the first time I've heard of anyone having this issue on any model Leaf.

sriram said:

Thanks for all the advice and suggestions! But I am still puzzled why this happened in 3 months in my brand new Leaf and does not happen in my Toyota Prius and Avalon, both in Phoenix over the last 18 months and several years in Phoenix. I thought recirc is the default in these also.

Click to expand...

Part of the reason is the seal. My LEAF with vents closed leak no air...at all. My other cars (including the Prius which had the same issues) did leak some air and I had others that felt like the fan was on low speed at freeway speeds.

I think in your case, the likelihood of your driving around with all the windows closed aggravates the situation due to back pressure preventing small air leaks. My Corolla leaked like a sieve but then again it was "older" and despite the definitive clunk of the vents closing, it still had significant air flow. The Prius also had that clunk which makes me think it was an electrically operated switch of sorts that released a spring loaded mechanism but the LEAF is all electric. The delay you experience when changing modes is more than enough to figure that out.

I can only think the "gentler" closing of the vent preserves the integrity a bit better?

Nubo said:

I also 2nd Lefties suggestion to turn off AC for a bit and let the fan run before shutting down the car. I try to do that when I'm a minute or two from destination. It's a good practice for any vehicle to help prevent funky HVAC odors.

Click to expand...

Thirded. It was difficult to get myself in the habit, and I sometimes forget still, but a few minutes out from my destination I turn off the A/C compressor, turn off recirculate, turn the fan to high, and crack the windows. Seems to work well as long as it runs long enough that the air coming out of the vents is no longer cool or wet feeling.