HVAC System and Duct cleaning

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SuperTramp

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Has anyone ever successfully completed HVAC System and Duct cleaning on your truck?

My ‘98 k2500 blows musty air in heat mode only. Several months ago, I cleaned/washed the coil and wiped down the blower motor mounted under passenger side dash with not much notable difference.

Earlier today I took dash face plate off and removed vent covers and generously sprayed Lysol in every vent and on the coil and I let it sit then used my leaf blower to move air throughout the duct system. Then I moved steam through the vents using our handheld cloths seamer. I also steamed the coil. Once I hooked up blower, the heater blew what seamed to be better smelling air, probably due to the Lysol. Hopefully it will also help kill the germs and anything else that might be growing.

Does anyone have any other ideas?

Thanks


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someotherguy

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Sure

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Z71Hobbs

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Short of actually pulling the entire system out of the truck and scrubbing it down (Lysol and steam will only do so much), cleaning the heater core area is about the best you can do.

I have a dash duct system from a donor dash, and I scrubbed the heck out of it. Some of the residue doesn’t want to come easily. Fun part of owning vehicles that are 20+ years old.
 

Deathpunch0311

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You can go on amazon and buy some stuff called sporocidin. It’s what I use with cleaning residential ductwork. It’s $30-$40 for a gallon but it gets rid of a lot of smells. I used it in my wife’s truck when she had a water leak from her third brake light and it caused a musky smell in her truck. When you get in it now smells like a brand new truck.
Get some of it, put it in a spray bottle and spray it into the return by the blower wheel. Let it run and it should do the trick for you.
 

SuperTramp

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Thanks for the information on cleaning the coil and duct work.

Do you know where the fresh air comes into the cab? I imagine somewhere on the firewall but I can’t find it.

Does anyone know if the ‘98 Silverado k2500 model uses a cabin filter and if so, where is it located? If Not, has anyone ever fabricated one?

Thanks in advance!

Wes


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df2x4

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Do you know where the fresh air comes into the cab? I imagine somewhere on the firewall but I can’t find it.

The fresh air inlet is under the black plastic cowl that the wiper arms stick through.

Does anyone know if the ‘98 Silverado k2500 model uses a cabin filter and if so, where is it located?

No cabin filters on any GMT400.
 

someotherguy

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The fresh air inlet is under the black plastic cowl that the wiper arms stick through.
Yep - on the passenger side of the "well" under the plastic cowl, there's a wall made of sheetmetal that surrounds the opening into the cabin. That's to keep water and most debris out of the fresh air intake. It still lets dust and some debris in which explains the crud you find attached to the evaporator core as I pictured above. You can't really see the wall or the inlet but with the plastic cowl removed you can reach in there and feel it. You'll notice there's a metal cover on the top of that area that is seam-sealed into place.

By the way if your plastic cowl design is the one that has a screw over that area (some years don't) be sure to use a little silicone on re-install or the screw can leak water directly down into the fresh air intake, causing your HVAC box to drip water on the floor (separate issue from condensation dripping.)

Richard
 

Lanny

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Yep - on the passenger side of the "well" under the plastic cowl, there's a wall made of sheetmetal that surrounds the opening into the cabin. That's to keep water and most debris out of the fresh air intake. It still lets dust and some debris in which explains the crud you find attached to the evaporator core as I pictured above. You can't really see the wall or the inlet but with the plastic cowl removed you can reach in there and feel it. You'll notice there's a metal cover on the top of that area that is seam-sealed into place.

By the way if your plastic cowl design is the one that has a screw over that area (some years don't) be sure to use a little silicone on re-install or the screw can leak water directly down into the fresh air intake, causing your HVAC box to drip water on the floor (separate issue from condensation dripping.)

Richard

Definitely remember to reseal it. The past owner of mine did not and water got in and ended up freezing my blower motor solid when the weather got cold. That was an interesting repair for me to do.
 

SuperTramp

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Thanks guys for the information


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Schurkey

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My '88 had a "poor heat" condition. Could not get the cab to warm up, even after half-an-hour at highway speed. Put in a 205 thermostat trying to get more heat (didn't help.) Strangely, the air from the heater duct was plenty hot.

Wife rides with me, complains about cold air coming from under the dash. Well, there's the problem--there's so much cold air pouring in, it overwhelms the heater.

Turns out, GM used crappy foam gaskets between the various parts of the heater ductwork, and the foam seal between the firewall and the inlet to the fan case was totally rotted away.

I had to remove the steering column, drop and remove the dash, and beat the hell out of the blower-fan box to get it out. (The instructions in my GM/Helm service manual were WRONG, and it was IMPOSSIBLE to remove the parts as they claimed.)

I replaced the original foam gaskets with Home-Improvement Store self-adhesive foam strips cut to fit and glued together as needed to seal the various joints. All the original foam that was still in place crumbled to jelly when I touched it.

Afterwards, the truck got so hot inside I couldn't take it. Replaced the 205 thermostat with a 195, and on longer trips I still have to turn down the heat control.

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If you've got evil odors coming from the HVAC system, verify that the HVAC drain is not blocked, and the rubber "duckbill" is in place. If the drain can't let condensation out, you'll have mold/mildew problems in the HVAC system that will NEVER go away.
 
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