Anybody know?

 

Probably because you have mildew in your AC.

Get a can of Lysol (spray),
Turn AC on, spray Lysol at the base of the windshield (outside).

Leave the windows open a little and let sit overnight.

If this doesn't work, you'll need to remove and replace the AC condensor.
Not an easy, fun, or quick job.


phox

 

The condenser is in front of the radiator, right?

 

Not to hi-jack this thread, but since the hvac subject was started; do these trucks have a cabin air filter? Heck our Freightliners do, and they are also a DC product........

 

I misspoke.
The part under the dash, which requires the whole dash to be removed in order to replace it.


phox

 

I think that is the evaporator

 

That's the ticket.

I knew it ended in "er" or "or".


phox

 

Geno's sells a cabin air filter kit for these trucks.

 

My evaporator started leaking on me.
So this is what i did last weekend, not too hard just a lot of work.
It'll take you all day to do it and a few extra hands will help out a lot.

 

I had the mildew smell as well on my '98. There are threads going on TDR and DieselRam.com about dropping the cabin fan (only 3 - 8mm screws) beneath the glovebox and cleaning out debris with vacuum and garden hose. You can also give your evaporator an enema by putting a length of heater hose on the firewall drain and using it to keep water inside.

I tried it on Friday by first vacuuming out some leaves and twigs that had gotten into the squirelcage fan and ductwork. I then gave the "enema" first using a mixture of Simple Green anti-bacterial cleaner mixed with hot water, followed by citrus orange degreaser mixed with hot water (to kill the Simple Green smell). After the enemas, I rinsed repeatedly with a garden hose into a pail so I could monitor the debris exiting. I had to rinse about a dozen times until the drain water was clear. The first few cleanings left really nasty drain water. After rinsing, I reinstalled the fan and took a long test drive with the fan set on high and on the floor setting. So far the mildew smell seems better, but time will tell.

A HVAC system cleaning was definitely overdue on my truck.

 

BC.. I can't remember.. but I was thinking there is a peice of foam in the bottom of the Evaporator housing.. and it tends to hold in the moisture... (but you really can't run without it... )
A few other things to try.. one.. the last few mins of driving, turn the dial to a vent position... Two.. look where the drain tube comes out.. its facing forward.. try adding some hose to it, and facing it more downward.. so passing air will help pull the water out... Some gassers had these...
Good Luck..
Bryan

 

Where is it on our trucks? My Chilton manual doesn't even mention it much less show how to replace.......

 

That because there isn't one. The Geno's product is aftermarket.

Best way to keep the mildew from forming is prevention. Turn the A/C off and fan on high a few miles before you park for the night to dry the system out.
No moisture = no mildew.

 

Before attacking that dash for an evaporator R & R, I going to try some of this "magic" sealer.

http://www.acsource.com/index.asp?Pa...ROD&ProdID=532

There's been several people around here who've used this stuff with lasting results....lasting (and working) long enough to get in the mood for the real repair, I guess. I'm trying this stuff before I tear into that!!
Good luck!

 

BG products make a couple of prod.http://www.bgprod.com/products/climatecontrol.html

Suppose to be good stuff.