Cadillac Owners Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter #1
When I turn on the air/heat on my 1994 SLS there is a nasty small, kind of like mold or something. It either goes away after a few miniutes or I get used to the smell, but I can't smell it after a few minutes of the fan running. Anyone have any idea waht this could be and how to fix it.
 

·
Registered
Joined
·
10,429 Posts
The obvious answer is moisture in your duct system. The questions are "What is the source of the moisture?" and "How do I get rid of it?"

If the source is still active then you have to find it and stop it. Sounds simple but...... the most likely candidate in my thinking would be the heater core. If that has developed a leak it will introduce coolant into your duct system and will need to be replaced. If you have noticed a slight drop in coolant level this might indicate a core leak. You may want to do a pressure test on your cooling system to verify.

Another possibility is condensation. It may be possible that you have moisture in the system from condensation, if this is the case then you should run your AC continuously to help remove that moisture. (AC dehumidifies the air.) This may take some time and patience but if the moisture source is not constant then the problem will eventually dry up.

One last suggestion, you may want to have your AC system checked and serviced to ensure that it is working properly, if not it could prolong your problem.

Hope this helps, let us know.
 

·
Registered
Joined
·
92 Posts
do not forget to check to see if the AC weep holes are clear. The AC system creates condensation which you see dripping on the pavement when you park the car. If for some reason the draiin is plugged that water will not be purged and mildew would grow.

once you have located the drain, you can try pushing a straighted metal coat hanger up the tube in a plunging fashion a few times.

K
 

·
Super Moderator
Joined
·
86,074 Posts
Usually the cause is as Kev mentioned, condensation from the A/C. As Kobo said, first check the drain and clear it. If a coat hangar it too big, try some weed wacker line (.080). To clean it you'll need to open the hood and look on the top of the HVAC housing, closer to the passenger side I believe. There should be an outline marked "CUT HERE FOR SERVECING"? After you cut that out, you can get at the A/C evaporator to scrub it with a toothbrush, rinse it slowly with water (the water should drain out the drain tube). You might also try cleaning it with something that will clean/kill mildew/mold. Then repair the hole you cut with duct tape, aluminum tape or a flattend piece of an aluminum can and RTV.

This problem is more previlent in hot humid climates (Gulf states). To prevent it from happening again do a search for Afterblow. This feature, when enabled, runs the blower motor for a few minutes on and off for an hour after shutdown to dry out the evaporator. You should be able to enable it through the onboard computer.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #5
I took some time today to check things out. It appears that thet heater / evaporator case has been busted up pretty bad and most of it is missing. The part where the access plate is is ok, but lower (behind the motor) is broken and mostly missing. I do not even see the drain tube and when I put a hose in the access plate area the water pours out the bottom.

I have some questions for you guys. What is the part number for this (1994 SLS)? How difficult is it going to be to replace? I think it has been like for some time as I know I did not hit anything (but I have only had the car for a few months). Whejn I use the AC it appears to cool the car down enough, but I never felt strong air thorught the vents (I assujmed it was supposed to be like that). The heat is barely felt at the lower heat vents when the heat is on. Can this broken area be just for the heat side of the blower? The car came from Florida and I doubt the heat was ever used.

Thanks for your inputs...
 

·
Super Moderator
Joined
·
86,074 Posts
That seem to be a rather common problem on older cars. Maybe they started using a better material a some point because mine is still intact and not brittle. That housing is not just for heat. It is where outside air is drawn in and then passed through the evaporator and/or the heater core. With that bottom busted out I am surprised that you have any air flow to the cabin at all if it is as bad as you say. I have no idea on a price but I think I have heard others say that it cannot be R & R'd with the engine in the car. This has been discussed before. Some have repaired it with duct tape and/or epoxy. Getting at it is the hard part.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #7
I am starting to think the smell may be a rodent that has crawled into the ductwork through this area. Is that possible? I am going to try to use my air hose and blow through the ducts in the cabin to remove whatever is in there. Is there anything I could damage with the air hose?
 

·
Registered
Joined
·
464 Posts
I just checked the box marked "cut here for servicing," and there is an "X" cut in it, left unpatched. I wonder if this is allowing moisture to enter and causing the nasty smell. Do I need to cut it to plunge the drain?
 

·
Super Moderator
Joined
·
86,074 Posts
No. You need to cut it only to gain access to the evaporator . Clear the drain from underneath. That "X" is not letting anymore moisture in than is getting in throught the intake vent when it rains.
 
1 - 10 of 10 Posts
About this Discussion
9 Replies
5 Participants
Ranger
Top