HCBPH: Do you use the "MAX A/C" setting on your truck all the time? When I encountered the same smell I began to run the A/C on "A/C" and after a few days the smell went away. The reason may be that "MAX" recirculates the cabin air, never allowing outside air in with any volume. When you turn the truck off for the night, the vacuum controlled air doors remain shut, keeping fresh air out. If you are doing what I described, try running w/o "MAX", and leave your windows cracked at night (if you can)...j.b.

------------------
99 SC Sport, Silver color everywhere, 4.2 auto,3.55 rear gear, split bench, stock AM/FM @ 2 cheesy speakers w/Ford brand bedliner. Keep'n stock from the factory because we love it for what it is...One fine ride!

 

I also have had the musty odor. Sometimes worse than others. The first summer after I bought the truck I took it into the dealer to have them look at it. They ended up spraying some kind of deoderizer in the air box. The service guy said it was mildew? He didn't offer any suggestions for keeping it away but it hasn't come back as bad as it was the first time. Try the Max a/c off idea first. If that doesn't work take it to the dealer and have them shoot some "bacteria killer" into it.

------------------
'97 F150 Lariat, Flareside, white/sliver, SC, ORP, 5.4, Mods: 305/70/16 GY ATS, AR Baja wheels, dual exhaust, Smittybilt Nerf Bars, Edelbrock IAS Shocks, K&N Filter and Carbon Fiber Bug Gaurd. Rigged the fog lights too.

 

Since buying my 97 last spring, it's had a musty smell for the first few minutes after turning on A/C, Vent, etc. I assume it's either water pooling from the AC or a dirty filter inside the housing. Water drips out the bottom when the AC is on so I don't think it's a plugged drain. I have not found a way to either open the housing without tearing out the dash or getting to a filter. Needless to say, I would like to eliminate the smell without disassembling a majority of my truck. Anyone have any ideas on how to eliminate the smell?

Thanks much

 

Being in the south, I run the AC on MAX a lot. I too used to have "that smell". What I do is when I know I'm about a mile from stopping the truck, I turn the AC to panel. It does start to get warmer but you're stopping soon anyways. And I don't have that smell anymore.

------------------
97F150 XLT SC 4x4 Flairside 4.6 V8 5sp Dk Toreador Red, 3.55LS
ARE tonneau cover, p255/70rx16 tires (came w/235), Superchip
Pioneer CD w/4 Polk Speakers & Clarion APA5240amp, skid plates
bed liner, side window deflectors, reese hitch, K&N air filter
40s-2chamber Flowmaster, Bosch +4 spark plugs, rustproofing
Better Built Stainless nerf bars

 

JB is correct on this problem...using Max AC will cause the mildew problem. Use Max AC sparingly and run in regular AC as much as possible. The important thing is to get outside air into the ducts, either in regular AC or by non-AC "panel" settings. I wish the auto manufacturers would come up with a system that automactically kicks Max AC into the regular mode after so many minutes.HTH.

------------------
F150 SC, 4x2, Oxford white, flareside, 5.4, 3.55 rearend,
Pending installation (on order)Nascar Penda bedliner, Snugtop hard tonneau.
Future mods, 2/4 lowering, bra, bodyside mouldings

 

Actually the so called "correct" procedure is to do the opposite of what Marv said. You're really supposed to run it on A/C first until it's cool inside (because it's usually hotter inside the truck than out) and then switch to MAX so that you're not constantly trying to cool the hot outside air. But running fresh air through the vents before you stop the truck does it for me, in fact if you read the owners manual it suggests that you leave the vents open overnight. There's also some suggestions on using Lysol through the A/C system on this board, you might want to do a search for that.

------------------
1999 Lariat Super Cab, S.B. 5.4L, 3.55 LS
and everything but the leaky slider window.
Bright red w/ gold 2-tone, Leather Captain's Chairs
Mods: Duraliner bedliner, Bugflector II, Hide-a-hooks.
& a leeetle chrome tip on the exhaust.




[This message has been edited by Indyfan (edited 09-07-1999).]

 

With due respect to Indyfan, "Max AC" should not be used as the normal setting; Max is the recirculation mode (as correctly mentioned by JB) and is used to quickly cool down the interior. The system should then be switched to "AC" for normal operation. The recirculation mode inhibits outside air from entering the ducts and encourages mold to form. I have a lot of experience with large fleet operations and could always tell which vehicles were left in "Max" due to the smell coming from the ac ducts. In fact, you could run your ac just fine without ever using the "Max" setting.

------------------
F150 SC, 4x2, Oxford white, flareside, 5.4, 3.55 rearend,Bodyside mouldings
Pending installation (on order)Nascar Penda bedliner, Snugtop hard tonneau.
Future mods, 2/4 lowering, bra

 

Oh... you people who live in the more northern climes really don't know what people experience in the humid south/tropics! Running the a/c on max is the norm during the day. It's the only way to get enough moisture out of the air to make it comfortable and get enough btus to counter the heat gain from the sun.

My procedure has been to start with a/c on max and fan High with windows open. As soon as the air coming out of the vents feel cooler than the ambient temps, I close the windows. As it gets cooler, I lower the fan speed. The only times I set the control to a/c is if lower fan speeds are sufficient to keep the interior comfortable and just before I shut the engine off (like it suggests in the manual).

The thing that's bad about the a/c position is the faster you pull hot humid air across the evaporator coil, the less moisture and heat it will remove. On High in the A/C position, the air will still feel humid and cool, but not cold enough to make it feel comfortable. On the two lowest speeds, the air will spend more time in contact with the coil so it will be drier and cooler and will feel more comfortable, however, it may not be enough to counter the thermal gains from the sun.

When you're at 90+ degrees with humidity at 80+%, you need all the cooling and dehumidifying power you can get. The A/C position just doesn't cut it.

 

Okay, some input from a guy in the a/c trade:

For starters, I happen to like that musty smell. Yeah, it's weird, but check my screen name. It's there for a reason.

And for us who live in the humid south, the "Max A/C" is the norm. Some of you, if you care to know, may wonder why today's a/c systems don't cool as well as older systems you may have had in the past. Well, thanks to the good ol' EPA and the ozone layer, the R12 refrigerant is no more. And it cooled a damn shade better than this R134A replacement. I've had cars with R12 plants that would freeze your eyeballs out regardless of the setting. And there's nothing better to me than a rolling deep freeze in the peak of a summer heat wave.

But I understand some aren't as nutty as I and dislike the musty smell. Drying out the evap coil for a few minutes by running the system on "Panel" is a good idea, as is spraying a disinfectant of your choice into the system's intake. If memory serves me well, the fan's intake is below the glove box on the passenger side. I'll check it out on my own truck to be sure, and edit this post if I've blown it.

 

Crazy C: I heard from a friend that they have started producing R-12 again. Is this true? You're definately right about R-134, it doesn't cool anywhere near as good as R-12. I miss it.

 

Frank,

An R12 re-phase in would be news to me. As far as I know, unless somehow the dictates of the 1986 Montreal Protocol, where approx. 70 industrialized nations agreed to phasing out all CFC and HCFC refrigerants by a certain time has been suspended, R12 is still history.

I have heard there may be better replacement refrigerants for auto a/c R12, superior to R134A. I would welcome this, as I can't always park under a shade tree during a 100+ degree day with the windows cracked and the sun reflector in the windshield. If I do that, my truck cools down quickly and I can take it off the max fan speed a lot sooner. If I don't, that sucker is cranked up for the entire 12 mile commute home, and struggles against the pent up heat. An R12 plant would NEVER do that, no matter how long the car had sat in the blazing sun, sealed up.

I drive my wife crazy. To me, a/c isn't working right unless I get that wonderfully refrigerated feel. Most of the time the F truck systems can do that, but a better refrigerant would really help. (F-150's have one of the better R134 plants...I've had some real dogs in other vehicles)

BTW, the evap fan intake on our trucks is indeed on the passenger side below the glove box, and I was surprised to see a filter installed. I've *never* had a vehicle in twenty years with a filter for the a/c system! Ford built a cool truck.

[This message has been edited by Crazy C (edited 09-08-1999).]

 

Thanks for the info. I talked to my friend again and he said it is a CFC-free r-12 they are making. He said it can be used in place of r-134 and won't hurt the system. I think I'll give it some time to see if it is ok though.

 

Actually I must confess. I have been going all over the country stuffing my dirty socks into your air intakes!

No...realy... if you want to, you can run the heater a little every other week to dry everything out in the box as well. Dry's it quicker than the vent setting. But I must reinterate that using Max AC most of the time in the South is just survival. Try running the heater just a few minutes before shutting down in the hot humid weather. Have some of you noticed this has not been as much of a problem this year in most areas due to the drought?

 

I appreciate everyones thoughts and ideas here. I'm definitely going to have to see if I can locate the air intake and get some Lysol or comparable in it. Unless I have the wife with me I normally drive with 'Go Conditioning'. That's where you have everything off, the windows open and Go Like Heck. She has asthma, so when it's hot out she needs A/C. Biggest thing is obviously I don't know what the former owner did, but for the most part I don't use A/C at all, yet if I have the control even on Panel, I still get those few minutes of musty smell.

Thanks again everyone

------------------
97 XLT Extended Cab 4X2, Northland Edition Short Box. Dark Toreador Red & Saddle Tan Accent. Tan Interior. 4.6L V8, 4-Spd Automatic. 3.55 Limited Slip Rear, Factory Bedliner, Non-Leaking Sliding Rear Window, Trailer Towing Package,LeBra Tonneau, with a 'Crack' in the drivers door.

 

indy fan= the opposite is the correct procedure. while it's true that most of the
time it will be hotter inside than out, using
max cools off faster, esp. in the humid southeast where the odor is more noticicable
than drier climates. start with max if really
hot/humid (i.e. heat indexes of high 90's or
above, but switch to a/c when truck/car cools.
this allows outside air to keep evaporator from mildewing. yes the manual says to use max, but that is some nut engineer trying to
save you a .1 mpg. from the compressor possibly cycling on and off. in temps. over
90, it won't cycle anyway probably. i do this
because i smoke, but have never had smell, but wife and son who like max better are always complaing about smells. once veh. cools off, a/c is quieter and allows outside
air to enter which is exited by relief vents
in the doors or other areas, and any time you
have a change in the air, you have a fresher
smell