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Mildew Smell in 91 NSX

Joined
28 July 2016
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7
I have a 91 NSX with 53,000 miles. Mint condition. I’ve noticed a mildew like smell and not sure where it’s coming from. Have a box of baking soda in car and keep windows down. Carpet is dry. Was worried something is leaking. Any ideas for how to better diagnose and who should do that? Dealer? Body shop? Detail expert? Thanks
 
Do you turn your air conditioning off and run the fan for awhile after a drive to get the moisture out of the system? If not, doing so may help with the smell.
 
There is a drain from the evaporator box that can become plugged over time. Under high humidity conditions the evap box can accumulate quite a bit of water when the AC is running. If that water is not draining out or is draining poorly, it can mix with dust and other detritus to support the growth of some pretty funky things that come with some pretty funky odours.

On a day when you have been running the AC for a while and the humidity is fairly high, park the car and let it sit for a while. You should get a puddle of water forming under the car as the condensate drains out of the evap box. On a hot day, my 2000 leaves a small lake and Saskatchewan is not noted for its humidity.

If you search, there are some fairly old threads describing cleaning out the drain hose from the outside. If its seriously plugged that may not be adequate. There are some equally old threads describing pulling the blower housing apart to get a more thorough clean. You may need to do that anyway if you have a serious mould farm going on in the evap box.

Air conditioning maintenance guys have sprays that they use to deal with the growth of undersireable stuff and there are also cleaners specifically for evaps. You might try an auto air conditioning place to see if they have those chemicals.

When I bought my NSX, it had a lingering 'aroma' in it. A few treatments with Fabreze did a remarkably good job of eliminating the residual smell after I cleaned the car up; but, you need to deal with the source. If the Evap is not draining, its going to be collecting water and acting like a petri dish for undesirable stuff.
 
Remove the blower motor and spray the hell out of the evaporator with that frigid fresh. :)
 
If you can't find Frigi Fresh (available on ebay) you can find similar AC coil cleaner at a hardware store. Also you can use a small paint brush or tooth brush to clean the coils.
 
Actually, before using strong chemicals on a part where cabin the air goes through (you breath in!) you might try simple 70% alcohol first. A drug store once recommended me a strong desinfectant where the list of negative aspects (cancer and all the hell) was so long that the writing was barely readable. Just a thought.
 
When I worked for MB we had a TSB for this problem affecting a range of 211's. The MB's solution was a branded mixture of 80 percent alcohol and distilled water run through the evaporator and system. I mention this because it's inexpensive than other options. I will also say this was a lengthy process. Expect to do it at least a few times! Also, another trick I learned from another tech was to leave the car out in the sun as well while doing this. Mold does not like heat and alcohol, unlike the rest of us.
 
Which vents exactly would you spray these cleaners in?
 
run an 03 ozone machine for an hour (AFTER CLEANING ALL AC COMPONENTS AS OTHERS HAVE MENTIONED ABOVE) fan on high with recirc on. This will/should get rid of that smell. Is there a cabin filter on these cars? Not sure, im new to the club :) If so, change that also.

Note: Do not be in the car when that machine is running, close all doors and windows. That stuff can do some serious damage to human physiology.
 
will running an ozone treatment have any negative effects on the interior? like it wont damage anything, would it?
 
Nah! youll prob run this machine twice in the cars lifetime if you dont live in a immensely high humid env. Run it for 45 minutes with the recirc function on high speed and that should be sufficient for a car this size. You wont do any damage to your leather/other components etc. FWIW this is what I use: Enerzen Commercial ozone gen 6k mg industrial 03 air purifier

Have used this on high end work orders w/out any issues. Use with confidence
 
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