Hey gang ... 97 Expo 5.4 L, front/rear a/c & heat

Having issues w/ the heater core (my baby is starting to iritate me - just replaced the alternator last week). I'm getting some "classic" symptoms like the rapidly fogging windshield, etc. But it's not smelling of antifreeze this time (had it replaced four years ago and I the smell was overwhelming) ... so could it be something minor (where I don't have to take out the dash to fix)? And unlike last time, even when I have the vents to panel and/or floor, the windows still fog up - last time it only happened with the defrost setting.

Anyway, I have combed through the forum and found instructions (thanks!) on replacing it but the instructions were for a 97 F150. While the two trucks are similiar, are there any nuances about replacing it in an Expo? And should the back be replaced as well? I want to do it myself (seen posts where the dealer has tried to swindel upwards of $1300 - I don't have time for that sort of foolishness!), but don't have the manpower (doing it by myself) nor the time (full time work and little daylight hours left by the time I get off.

And in the meantime, I'm freezing my tail off! Any tips/hints/tricks would be greatly appreciated. I've got to find an electric blanket I can plug into the lighter!

 

You may want to have your A/C system checked. If your windows fog up and your not smelling antifreeze I'm going to guess your A/C system is not pulling the humidity out of the air when you have your heater on defrost. One way to check is to start your vehicle put the heater on defrost and check to see if your A/C compressor comes on. If not it may be as simple as adding some freon to your A/C system.

 

Thanks for the reply Skypilot957! I'll stop by AZ in the morning and add a can. Will post back with results. But question: the windows fog up even if I have the heater on panel, panel/floor too - not just when on defrost. Does that matter?

 

You need to have your pressures checked on your A/C system before adding a can. You don't want to overfill it!

As far as I know your A/C only comes on when you use the defrost mode. Do you have the climate control where you set the temp and it will automatically decide if you need A/C or heat?

 

No auto climate control. I didn't get a chance to have the A/C pressure checked (unexpected errands) but plan to today. But now I think something more sinister is going on....

The windows are now fogging up even if I DON'T have anything on. Everything is shut off and I even closed the vents - "the mist" still came back. Thinking I could be contributing from the vapor expelled from simply breathing, I left the truck running for about 30 minutes last night while I went back inside the house. I came back out and you guessed it - nice and foggy. Thinking I would be clever, I stuffed paper towels in the defrost vents near the windshield - thinking it was coming up through there. Well, that seems to slow it down, but it's still fogging up. And of course when I cut on the defrost - either hot or cold - it gets worse.

Help???

 

Well, got the A/C checked and it's not the compressor ...

 

Did you start your vehicle and put the heater on defrost and check to see if your A/C compressor comes on?

Have you left your windows down while it was raining? Is the interior damp or wet for some reason? Sounds to me like you have an unusual amount of moisture inside your truck. Check to see if your passenger side floorboard is wet. Matter in fact check to see if any of your carpets are wet. If they are you may have a doorseal that is bad and allowing rain or moisture thru to the interior. If not then I'm at a loss as to what the problem is.

Maybe someone else may have a suggestion to help you out.

 

Checked the carpets and floorboards this morning after reading your post and again when I headed out to lunch. Checked the front, middle, back.cargo area - even put my hand as far up in the dash as I could reach to check if anything felt damp and got nothing. Nothing is wet or remotely damp at all. But something peculiar did happen on the way to work though ...

I pulled a McGyver and put duct tape over the vents before I left - figured it couldn't hurt to try. My commute to work is anywhere from 45 minutes to an hour and since this has been going on, the windshield starts getting hazy usually about 15 minutes into the drive; at 30 minutes, I'm having to wipe a "porthole" through the fog in order to see. But after taping up the ducts, this was the first time in WEEKS that the windshield stayed clear. It was great!

But then, about 15 minutes out from work, I started noticing the windshield getting a little hazy and out of the corner of my eye, I saw a faint, small vapor trail coming out of the cabin vents near the radio (didn't tape those up). It had no smell at all - not smoke and not antifreeze. But I'm figuring this HAS to be antifreeze to fog up my windshield, correct? I checked under the hood, leaving the engine running) to see if I could spot a leak and saw nothing. The coolant level was the same as where I left it last week when I filled it a bit over the max fill line.

What gives? Anyone? I'm at a loss and my last resort is, unfortunately, taking apart the dash to replace the heater core.

Thanks for the suggestions and assistance in advance!