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Evaporator Odor Fix

Gary Harrison on Mon October 22, 2007 1:04 PM User is offline

Year: 1997
Make: Acura
Model: 2.5 TL
Engine Size: 2.5L
Refrigerant Type: R134A
Country of Origin: United States

I have recently had a problem w/ bad smell (dirty socks, wet diaper bad but not horrible) coming from the evaporator after sitting for a few hours. Particularly noticeable on first start in the morning. This arose after repairs idled the car and was parked outside for 3-4 wks.

I first tried to clean by pulling disinfectants (Lysol and Consan Triple-20) through the fresh air intake. It was obvious that very little was getting to the evaporator since you could barely detect any smell in the air from the vents. As suspected, the attempts had no affect on smell next morning at first start.

I briefly considered discharging the AC and removing the evaporator, however a thorough review of the evaporator removal steps persuaded me that was a mistake. The evaporator is sandwiched inside the climate control module under the dash and must slide out sideways. Lots of items to remove and access is poor. Given the AC performs well otherwise, I decided to look at other chemical injection possibilities. The DWD2 Odor Removal system (see below link) is an option but requires placing a hole in the evaporator case and access to install an injection head. It was unclear how this would work w/ the unusual evaporator arrangement in the TL's.
DWD2 Odor Removal

I looked again under the dash and noticed one good thing. The drain hose is readily accessible on the pax side near foot postion on the trans tunnel upset. I decided to try chemical injection via this path. Following are steps I employed:

1) Remove drain hose after allowing system to dry overnight
2) Attach a short length (~4 ft) of clear plastic vinyl tube (~13mm ID). It doesn't fit perfectly but will engage the drain fitting on the evaporator case. Check frequently as it tended to come loose.
3) Suction any retained water w/ wet vacuum from the case.
4) Use an air compressor and siphon injector (picks up liquids w/ a pickup tube to the reservoir and injects them w/ the air stream), inject cleaning solution. I used Simple Green mixed 1:6 w/ water for cleaner. The air injector facilitates blasting the cleaning solution up into the evaporator housing through the clear tube. I did this repeatedly, allowing material to drain out, then reblast w/ air-only over and over. Afterwards, use the wet vac to suction out cleaning fluid. In my case the cleaning returns were slighlty dark but nothing dramatic. Note, I used perhaps 1/2 pint of cleaning solution and other components below. You don't want to inject so much fluid you cause a leak from the evaporator case.
5) Repeat 4) w/ fresh water to flush the Simple Green cleaning solution.
6) Repeat 4) w/ disinfectant (Consan Triple-20). I tested this on aluminum to confirm it is non-corrosive. There may be other chemicals that are better?
7) Allow Consan disinectant to completely dry (per instructions).

I drove car yesterday and mercifully the smell was absent. It's too early to tell if this is a permanent fix, but I'm hopeful. The procedure is pretty simple to implement and I suspect there are others w/ this problem.

Any comments, other cleaning or disinectant chemicals, or other approaches appreciated.


See you down the ROW.

NickD on Mon October 22, 2007 2:39 PM User is offline

I removed the blower motor and attempt to vacuum out as much as possible, can barely reach the evaporator. Wild idea was to start the engine to get engine vacuum, put the mode switch in vent, close all but one, duct tape the end of my leaf blower to that one vent, put my shop vacuum in the blower motor hole and switch that on first then the leaf blower. But talk about a 30's dust bowl storm! Have to get either a less powerful leaf blower or a more powerful shop vacuum.

All that road dirt settles someplace, smack on the face of the evaporator fins. Also find all kinds of junk in the recir door path, but never anything of value, darn.

Dougflas on Mon October 22, 2007 4:42 PM User is offline

And the cause of this problem is..... (Drum Roll).... not turning the AC off five minutes or so before the engine stops. Now who would do that? There are some fixes for this though. There are timer relay circuits that keep the blower motor running after the vehicle is shut down. It in effect dries the evaporator off. Ford early Focus cars had this problem if I remember. Maybe some one can find a TSB.

Gary Harrison on Tue October 23, 2007 7:40 PM User is offline

This takes a lot of discipline to insure. I don't think it's a necessity if you occasionally clean the evaporator. At least I hope that's the case.

There seems some possibility that some of the smell may have been coming from the cowl drain basins. They may have acccumulated some organic material also. I plan to remove the cowl covers and inspect them.


See you down the ROW.

Wet in Washington on Tue October 23, 2007 8:06 PM User is offline

So, is there a timer one could add to run the fan after you shut off the car?

Never take life seriously. Nobody gets out alive anyway.

NickD on Wed October 24, 2007 9:17 AM User is offline

Besides that odor, may learn that your evaporator is rotting out.

iceman2555 on Wed October 24, 2007 3:48 PM User is offlineView users profile

The fan control unit is called an Electronic Evaporator Dryer-5. It is available at GM and other retail locations. It wires in series with the OE wiring harness and allows for blower operation after engine shut down. There are safety designs to prevent long periods of prevent battery drain....and others.
It is a straight forward installation for GM and for others if one is good with electrical circuits.
The evap is, unfortunately, a great place for mold/fungus to developed...a dark, moist area.....mmmm.....sounds so nice.....a bit smelly.....but great place for those mold presto grow and reproduce more spores....
This condition normally occurs in the more humid locations of the US....and in vehicles where the MAX cool option is used intensively....using the A/C in NORM does tend to reduce the build up of this material. Just something I read.....
One of the options for reduction of this was to shut down the A/C and run the blower for about 5 minutes to aid in drying the evap......yeah...right.....hit the drive...shut the engine down....and in the house....looking for a cool or simply a soda.....easy chair....catch the latest propaganda...opps evening news.....and yell at the other half to get dinner on the table....!!!! Who has time to run the blower......
The modules are in the $100 range...and figure about 45 minutes to install and test.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

iceman2555 on Wed October 24, 2007 3:55 PM User is offlineView users profile

GM has a service bulletin conderning this 'option' on some GM bodies....check it out...99-01-39-004A is the tech bulletin. The EED5 is available from AirSep or maybe TRB has them also...not sure....but buy from TRB first....he needs the his eyes on a new mountain bike.....

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

TRB on Wed October 24, 2007 3:58 PM User is offlineView users profile

Originally posted by: iceman2555
but buy from TRB first....he needs the his eyes on a new mountain bike.....

Not true, I'm just upgrading!

When considering your next auto A/C purchase, please consider the site that supports you:

NickD on Thu October 25, 2007 7:24 AM User is offline

Ha, I don't switch off the AC when stopping off at a bar to have a case of beer with the guys, only there for less than an hour anyway, but even in that intoxicated state, when near home where my cars spend 99% of their time and I know I am going to sleep off that indulgence, my finger automatically goes off to hit the Econ or Vent switch and puts the blower in the maximum position so I don't end up with a huge puddle of water on the garage floor.

My finger could be replaced by a timer, well not totally, have other uses for my finger, try picking your nose with a timer, LOL. Just more expense and something else to go wrong, but that goes against the trend about adding a bunch of stuff that goes wrong. Just ask Joe about all the fun he is having with his Caddy.

Gary Harrison on Thu October 25, 2007 9:05 PM User is offline

I could rely on moi, but my wife, son, daughters are hopeless. They look at me like I'm from Mars when I tell them such fine instructions as; when you fill up always reset the trip odometer, check the oil and radiator, etc. I suppose I've spoiled them. They know enough to call Dad when it "won't go".


See you down the ROW.

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