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Yet another 'Car smells musty' thread

Hello folks,

Lately, my 2006 Sentra (~103,300 miles on the odometer) is smelling musty. I had a light whiff so far but last week, I tried recharging AC system with refrigerant. It leaked within a day, but I ran the system for about half an hour after charging the unit. Since then the smell has worsened. The evaporator drain is not blocked.

I checked the old threads and @Beadsandbeads has contributed a lot to such issues. I just don’t know if he/she is still active on the board. I will follow all the directions suggested by @Beadsandbeads

To address the situation, I first need to clean up the system. @Beadsandbeads suggested the use of AirSept products but I can’t find these products for sale for a layman. If possible, I do not wish to spend money on fixing AC system i.e. fixing leaks in the AC system, adding refrigerant etc etc because I am sure, its a money pit. Things are going to break due to aging and I will have to keep spending more and more to maintain the system. Plus, God forbid if its in the evaporator core. Removing Evap core of my car is a very time-consuming process (have to remove the whole dash) and at $98/hr, I will be paying at least $600 just to remove and put it back. What I am not sure if these leakages are the cause of this musty smell and if not patched, this will be a recurring event. I don’t mind adding cleaner every 3 or so months. That will cost a lot less than making and maintaining that money pit.

To conclude,

Any other ideas?

Thanks in advance.

I would suggest cleaning and thoroughly drying the carpets, upholstery and headliner before digging into the HVAV system. Remove the threshold plate on the passenger side front door and lift the carpet to check for a damp carpet cushion. Lift the trunk mat and check for moisture under it. Look in the spare tire well. Shake the doors and listen for water sloshing around. As for the HVAC, look in the fresh air intake below the wipers. It may have damp leaves settled in the bottom.

Something I’ve tried that successfully removes the funk… Odo-Ban. Mix up Odo-Ban into a bucket of warm water and pour it down onto the base of the windshield into the air intake on your car while the heater and fan are running. It doesn’t need to be warmed up. Shut it off and let sit overnight. Air it out in the morning. As the Odo-Ban smell dissipates, the funk should too.

@Rod_Knox I check car interior often because DS is highly allergic to mold and mildew and its clean. There are certainly some leaves in the air intake system that I plan to clean this week.

If I understood correctly, I pour this liquid into air intake. How long should the heater and fan run after I am done pouring into air intake? I assume, you need heater and fan running so as it flows through the system? Do I need to replace cabin air filter after that?
I wonder where does this water go? Does it evaporates or drains out from where the AC water is drained? Apologies for not using correct terminology but I am not very clear about the system.

Thanks again.

Edit: I just opened the air intake area to see if I can do this by pouring in air intake. What I found is, there is a trench under the windshield that houses windshield wiper motor. The driver side has air intake mesh and at the end of the passenger side of the trench, there is a wide hole, through which I can see the cabin air filter.

I have not posted to this forum for a very long time. I’ve learned some about cleaning auto AC systems since then and a lot more about residential. My advice was probably predicated on easy assess to the AC evaporator “coil” I can get to mine by just pulling the blower motor. It is a piece of cake. I can’t imagine that there is an easier vehicle for that access.

Foaming cleaners are good for small scale stuff and that is fine for autos, but again, access. You can use any kind of cleaner provided the exposure is short and you can rinse well. Prolonged extremes in pH need to be avoided. Ten minutes exposure with a clean surface is sufficient. Slightly alkaline, pH 7.7-9 is a good target. There are commercial cleaners out there just for this purpose. I 've been using Nu_Calgon products, Evap Pow’r-C and Evap-Fresh. You might finish by dropping a gel tab onto the top of the evaporator coil.

If you can’t get to the point where you can see the cooling coil, or nearly so, it is going to be difficult to clean. Condensate and anything that you run over the evap coil should drain out via a normal drain hole or hose. You need to check to be sure yours is clear and not clogged up. If you can’t get to the coil to clean it, you might consider something like the Evap fresh. Another thing that inhibits microbial growth is copper. A copper wire in the right place could reduce your problem considerably.

Unfortunately, disinfecting the system will have limited utility. It will be reinnoculated with microbes immediately. Soil in the system feeds growth and needs to be removed for any real solution.

See the below link to information about disinfectants. What you will run into mostly for AC systems are quaternary amines and phenolics. Old-fashioned Lysol was a phenolic, but I don’t think they use that formulation any more.

Refrigerant leaks are not going to cause microbe growth in your car’s HVAC system. Refrigerant leaks will just make it work poorly or not at all.

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What about turning off the ac maybe at least 6 blocks before you shut the car off and leaving the fan running, that may help reduce the moisture that feeds the mustysmellmakers.

Thank you @Beadsandbeads for stopping by to answer the query.

The evap coils are impossible to access unless I remove the dash completely. explains removal of evap core and the worse part is evap core is enclosed, so its not like you can sneak in using snake pipe to spray something. At 4.10 in this video, the guy removes the ‘box’ that contains evap core.

If this drain is same as where the AC condensed water drains, then it is not clogged. It drains very well.

How do I use this Evap Fresh if I can not access the coils? Can I get an aerosol and spray in through the drain hose?[quote=“Beadsandbeads, post:5, topic:105584”]
Another thing that inhibits microbial growth is copper. A copper wire in the right place could reduce your problem considerably.
Conceptually, I agree with the idea. The only issue is how to put it in practice. I don’t know how other vehicle’s air intake systems are designed but in B15 Sentra, there is a trench under the windshield that has windshield wiper motor and at the very end of the trench, away from intake mesh, there is a huge hole, through which I can see the cabin air filter… The cabin air filter is charcoal lined so I don’t know if it will adsorb copper on it. Below the air filter, there is blower motor and rest of the air circulation circuitry.

I am sorry, my comment may sound silly, but I am really at loss on how to get this working, esp when I know there is a leak in AC system and probably all refrigerant has leaked out…

Thanks again for your comments.

Consider it confirmed.

Fix the system first, then deal with the musties.

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Mostly just the vapor. It won’t and shouldn’t circulate the liquid. Just trying to get things coated a bit so the detergent kills bacteria. Pours it right into the area where the wipers are. That’s where the air intake is. Consider it as “disinfecting rain” The drain inside the AC system should take care of any liquid that gets in.

Those sprays you showed and others like them can be shot right into the air filter area. Take out the filter and fog the inside with fans running. Let sit overnight. I did that with a “smoker’s car” I bought to rid the tobacco stink.

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Thank you everyone for the comments.

Before I put everything in action and make fool out of myself, here are the pictures of the cowl trench,

From the driver’s side

From the passenger side

If there is any change in direction. I will be putting it in practice on the weekend.