Annoyed

After replacing my AC compressor, condenser and receiver dryer it looks like I am going to need to replace the ac EVAP module behind the dash. My guy evacuated and refilled with freon and dye. He is going to check again when I come back in a week but if he does not find the leak he said it's inside and he usually does not miss. Also, I do randomly have a must or mildew smell in the cabin. I have a feeling I'm going for another $6-800. I guess it's just one of those things for buying a 20 year old car, you never realize how much stuff you're going to have to go through even with low miles.

Damn though that's rough.

Thankfully I have it, I just don't want to part with it LOL.

carguy8888 wrote:

After replacing my AC compressor, condenser and receiver dryer it looks like I am going to need to replace the ac EVAP module behind the dash. My guy evacuated and refilled with freon and dye. He is going to check again when I come back in a week but if he does not find the leak he said it's inside and he usually does not miss. Also, I do randomly have a must or mildew smell in the cabin. I have a feeling I'm going for another  $6-800. I guess it's just one of those things for buying a 20 year old car, you never realize how much stuff you're going to have to go through even with low miles.

The musty smell just comes from crap (crap = technical term for organic flotsam and dusts that collect in the air box) that filters in thru the cowl vents. You can definitely get rid of the smell.

In general what you do is make up about a gallon of any reasonable enzyme-based cleaner, such as a carpet cleaner, pet odor eliminator, or laundry detergent. Really... as long as the cleaner uses enzymes. You just need a deodorizing concentration, which isn't likely to be much. See the product label for details. If you use a laundry detergent with enzymes, for instance, a capful makes 15 gallons or more of cleaning solution (wash cycle water). So to make just a gallon you are talking maybe just a tablespoonful. Then you simply pour that solution evenly down the cowl vents. After a day or two, pour a gallon of hot tap water down the vents to flush out debris, then make up another gallon of cleaner and pour that as before. What you are doing with each cycle is letting the enzymes "digest" the organic matter that's causing the odors, then rinsing out the detritus. Why this works? The cowl vents have screens, so the detritus is usually rotting pollen mixed with soot or other moisture-holding particles that will indeed flow out the drains if you rinse it out, and if it does not rinse out -- once you denature the stuff with the enzyme it will quit stinking. In my experience, one cycle of this cleaning may be enough. Nothing's getting damaged, though, so you can repeat this cycle until you get those boxes flushed. When I had to do it the first time, I did it for a few days. Since then, just occasionally. I've gone a few years at a time without bothering.

For a cleaner I use Odo-Ban made to Deodorizing (5 oz per gallon) strength. https://odoban.com/product/multipurpose-concentrate/ - originally it contained enzymes, I don't think it does anymore (they sell versions that do) but it seems to still work fine. At this dilution rate that gallon ($9) will last more than 20 years.

BTW the sprays in the dash vents and what not are, IMHO, a (colossal) waste of time and money as there is no place in those vents for organic matter to collect. It's all in the silly air box.

As for the evaporator, maybe it's leaking and maybe it's not. One of the problems with the current refrigerant (R-134) I am told, is that it eventually it seeps through the soft hoses. A leaking evap smells sweet, not musty, really. The seals at the evap connections are usually what goes. Given the trouble to replace the seals and the low cost of the evap coils, many if not most technicians will replace the coil anyway since they kind of embrittle due to cooling cycles in normal service. BTW in older R-134 systems, if you don't use them about all the time they leak like sieves because the seals dry out, and the hose seepage is a persistent problem. I 'top up' my AC refrigerant every 3 seasons or so. No stop-leak (gums up the compressor). Oh, and by the way, R-134 leak detectors are not pricey. if you or your AC tech don't have one, consider getting one and giving it to him after your repairs are done.

The smell I get is intermittent and definitely not sweet. I was planning to clean the air box out with Lysol spray but your way is better. since this car was owned by a 90 year old lady I have a feeling the air conditioner was not used often. I am using the air-conditioning this week with the dye in the system so next Saturday my mechanic we'll check for leaks in the engine bay again. If I unfortunately do have to go for a new evap is there a particular brand I should buy or it doesn't matter because I want to do this once? Also if I do have to remove the dash will I have access to the air box? As usual Albert you're always helpful.

https://www.rockauto.com/en/catalog/buick,1998,riviera,3.8l+v6+supercharged,1303322,heat+&+air+conditioning,a/c+evaporator+core,6768

I think the console has to come out.

If a PO smoked in the car, that will get into the HVAC system and ferment.

Thanks Larry, I was told it does. The part is not a problem, I just wish I did not have to take the whole car apart to get to it but we'll see on Saturday.

carguy8888 wrote:

The smell I get is intermittent and definitely not sweet. I was planning to clean the air box out with Lysol spray but your way is better. since this car was owned by a 90 year old lady I have a feeling the air conditioner was not used often. I am using the air-conditioning this week with the dye in the system so next Saturday my mechanic we'll check for leaks in the engine bay again. If I unfortunately do have to go for a new evap is there a particular brand I should buy or it doesn't matter because I want to do this once? Also if I do have to remove the dash will I have access to the air box? As usual Albert you're always helpful.

I'd have to look in the factory manual but I think to pull the HVAC air handler box you need to pull the console not the dash.

As for the "leak" - R134 has a 30% faster leak rate (all other things being equal) than the old R12 did. See this for more about HVAC in your Buick: https://www.youtube.com/watch?v=vDbKbBQ-M_Q

I'm going to go back Saturday for the first round and see if they find a leak. Also, I like your cowl deodorizing method. a while ago I watch some YouTube videos with people spraying Lysol and leaving it overnight but I think I'll try yours.

carguy8888 wrote:

I'm going to go back Saturday for the first round and see if they find a leak. Also, I like your cowl deodorizing method. a while ago I watch some YouTube videos with people spraying Lysol and leaving it overnight but I think I'll try yours.

If you look at a diagram of the hvac distribution box, you might well conclude for yourself that there is no way any Lysol(r) spray is going to get into it from the vents.

Not from the vents, spraying into the cowl.

carguy8888 wrote:

Not from the vents, spraying into the cowl.

No - but you could mix a solution of lysol(r) liquid and pour that in. Problem is, it won't digest the organic matter, so when it is gone eventually the air will stink again.

I'm going to do it your way.

Albert,
Just looked at the link you provided for the anti-bacterial product.
Looks like I can use it in my HVAC system(s) in my truck and G/F's car but also as a countertop and everything spray, when diluted properly, also.
I may order a gallon soon as now I know I can consume it in a relatively short amount of time.
Not 10 years+.
Thanks,
Rick

p.s. Where do you buy yours from. At a store or online.???

Does the HV AC system need to run at any point after the cleaner was poured in or just let it sit?

carguy8888 wrote:

Does the HVAC system need to run at any point after the cleaner was poured in or just let it sit?

In my experience it does not matter if you run it or let it sit, but you *should* let such a deodorizer sit long enough to dry naturally, which if you pour it in like I suggest will be a day (24h) or so..  When I do it, I  let it sit so that some of the eucalyptus smell dissipates before i have to drive somewhere.  I am not allergic to eucalyptus but I don't particularly like it.

Why odoban still works without the enzymes, I am not sure. It could be the eucalyptus oil, however. That oil is a known antiseptic in its own right.

Rickw wrote:

Albert,
Just looked at the link you provided for the anti-bacterial product.
Looks like I can use it in my HVAC system(s) in my truck and G/F's car but also as a countertop and everything spray, when diluted properly, also.
I may order a gallon soon as now I know I can consume it in a relatively short amount of time.
Not 10 years+.
Thanks,
Rick

p.s. Where do you buy yours from. At a store or online.???

Got it from Sams Club.  Check on line to see if it is in stock.  They used to always have it, when COVID-19 hit and people 'rediscovered' it, that was all she wrote.

Be sure to consider getting an *enzyme-based* cleaner to break up the organic matter.  Although, as I said before, the odoban seems to work fine. When I first used odoban the standard formula contained the enzymes. The current formula does not.

I ordered nature's miracle urine remover. It says it's an enzyme-based cleaner, I had good results with it years ago when I had a cat.

carguy8888 wrote:

I ordered nature's miracle urine remover. It says it's an enzyme-based cleaner, I had good results with it years ago when I had a cat.

Makes sense.

After your prior message I did some investigation into eucalyptus oil... I had no idea about the stuff. Turns out it is naturally anti-bacterial and anti-viral. People dab it on cold sores and such and it works - see this article republished by NIH: https://pubmed.ncbi.nlm.nih.gov/11338678/

So -- the thing is, that component of odoban (eucalyptus oil) would denature the organic mater that is causing the stink, after the detergent in it breaks any biofilm layer on the germs. Now I get it. That's my guess as to how odoban works, and explains why they could de-formulate the enzyme component.

Oh by the way -- if the odor is stubborn after you use your enzyme cleaner, re-apply it but add some hydrogen peroxide to the solution. The peroxide will release oxygen into the solution without much prompting, thereby encouraging the enzyme action.


Albertj

Another good idea for the hydrogen peroxide.

I ended up buying Natures Miracle urine destroyer which has the enzyme cleaning agent. It smelled lemony fresh coming thru my vents lol. I will flush it with the hot water tomorrow and maybe do one more round. Also, brought my car back to the shop after installing the dye and there was a bad o ring by the condenser. Free is much better then $6-800 to r&r the dash. Albert to the rescue again with your giant wealth of knowledge.

carguy8888 wrote:

I ended up buying Natures Miracle urine destroyer which has the enzyme cleaning agent. It smelled lemony fresh coming thru my vents lol. I will flush it with the hot water tomorrow and maybe do one more round. Also, brought my car back to the shop after installing the dye and there was a bad o ring by the condenser. Free is much better then $6-800 to r&r the dash. Albert to the rescue again with your giant wealth of knowledge.

No leaks by the evap? (I hope not)

When they found this leak they stopped looking. My mechanic suggested the EVAP if they could not find a leak in the engine compartment, thankfully they did.

carguy8888 wrote:

When they found this leak they stopped looking. My mechanic suggested the EVAP if they could not find a leak in the engine compartment, thankfully they did.

As long as they looked for dye spray bu the area where the refrigerant tubing goes thru the firewall, you're fine.

Albertj

So far so good.