Heater ductwork odor

[Cruize]

I've searched the forum and read a bunch of posts, but didn't find anything to match my problem exactly.

I've got a 95 Blazer, and when I run hot air through the heater ductwork, there's a foul odor that comes out. If I send hot air through the vent ductwork, there's no smell.

My sister-in-law's 96 Blazer just started doing the same thing last year.

Do I assume that a mouse / rat / or some other creature died in the heater section of the ductwork?

Does anyone know if there is a diagram anywhere that shows the routing of the ductwork through the truck?

Thanks.

[kb3jhp]

try http://www.partsamerica.com/ProductD...partnumber=PA2

[dmbrisket 51]

i assume they both have ac, i know this because it bacterieal growth in the drip pan, either the vent needs un-plugged, or you need to turn the ac off a few minuts b4 you get to a destination you plan on being at for a bit

[Cruize]

Sorry, but the AC does not produce the odor. Another car of mine does the musty odor at AC shutdown, but not the Blazer. In the winter when I need heat, if I run HOT air on the heater setting (air coming out near the floor), it smells. So, I've been running HOT air on the vent setting (air coming out the dashboard) to avoid the smell.

Sorry for the incomplete posting last time.

[dmbrisket 51]

there is something in the ductwork then causing the oder, a dead rodent, moisture causing a growth (ie mildue, mold) that should be taken apart and cleaned out good, mold has the potental to be deadly

[rlith]

You sure it isn't antifreeze?

[N8SBlaze]

I had a similar problem a couple years ago, and found that I had a very small leak in my heater core. The service tech said that my ductwork was FULL of black mold. Had the heater core replaced and the ductwork cleaned and has been fine since.

[Cruize]

I haven't noticed any moisture coming out the ductwork, so I never considered antifreeze.

Was all the ductwork full of mold, or just a portion of it?

I'll have to try and "snake" the ductwork to see what's in there.

[N8SBlaze]

I don't know how much of my ductwork was full of mold. The problem surfaced early in the winter a couple years ago. The duct work stunk for a couple of months. And then one day the heater core let go and had some steam come out the vents. The auto tech, whom I trust, had told me that it appeared that I had a small heater core leak that had caused the foul odor and mold problem before the heater core failed completly. I do not know if this is your problem exactly but it is something to consider.