Defrost making things worse

[stonerhino]

It's been raining its butt off here in Virginia for the past 3-4 days. The obligatory window scum easily dispatched by a few seconds blast of the defroster and I'm good for about 10 miles.

The scum issue is not really a problem. I detailed cars during my many years of unemployment, so its a non-issue. A good grease absorbing microfiber cloth rips it right off.

So today driving to family on thanksgiving, my window started fogging up. I hadnt driven 100ft from my parking spot in front of the house when the breath of everyone started to fog things up. I turn the defroster on and it worked great for about 3 seconds, then got worse. I had a passenger clearing the window off every chance we got to stop. Thankfully lots of red lights. I let the car warm up before the short 3mile drive back home and it just didnt do anything except blow hot air.

Once home, I popped the hood to check on things. Nothing sounded out of the ordinary and no smells, I cut everything off, unloaded my weary mother back into the house, and came back out dressed to destroy.

I started the engine and turn defrost on. Compressor cycles for 2 seconds and cuts out. Engine was now at running temp, dialed heat. Zero help. Switched to cold. No change. I dont have a recirculate button, so that was not tried.

I check my mothers F150 to see if it's really just one of those days, or if I had a problem with the freon system. Same behavior, except within 1 minute of engine running, it was starting to defrost even with the windows down and the wind blowing through the cab. The compressor cycled out after 2 seconds and never came back on.

I drove this yesterday (Wednesday) 30 miles in rain, without issue in the same conditions.

Suggestions anyone?

 

[briwayjones]

When on defrost it will automatically run the AC compressor to take the moisture out of the air. If your compressor is continually cycling on and off every few seconds than it sounds like you're out of freon. And the compressor isn't staying on long enough to take the moisture out of the air. With that being the case once it warms up and it's heat coming out I would think it would do something. When it's not real cold maybe turn the AC on and see if it works to confirm or not whether you have freon?

 

[stonerhino]

I was considering checking the freon, but again, my mother's F150 does the exact same thing and it defrosts. The compressor cuts in once for two seconds and never reengages. I waited for 6 minutes for it to cut in. It was nice and warm, but it barely put a dent in the stuff on the window.
Its too dark for me to whip out the 134a equipment, so I cant check that ATM. Was going to drop it off at my grandfather's place and swap back to the mustang for a day until it warms up enough that my fingers didnt freeze through 3 sets of gloves.

 

[briwayjones]

If you have freon, and if I remember correctly! If everything is working like it should then the compressor should kick on for about 10 seconds once every minute or so. But I could be wrong I'm going off of my memory and I haven't used my defrost in a while.

 

[stonerhino]

It's apparently too cold for the compressor to cycle in. This morning there is plenty of static pressure on the freon lines. Im figuring that the humidity was just too much without the compressor running. Its like the computer had it locked out.

 

[Number4]

Is warm air coming out of the defrost vents?

 

[stonerhino]

Yes, once the vehicle is warmed up warm air comes out. Its been working stellar since that day .

It was 40 deg, dewpoint was 37, and relative humidity was 100% + rain. Needless to say it was a rather icky day when all that happened. I guess I am going to have to wait until the next time the weather gets this way to check things out. It just seemed odd that not even warm air after 5 mins of engine idle wouldnt put a dent in it.

It was in the mid 60's today (felt like spring). I've cleaned the window again now that it has been dry as a bone and the remaining scum wiped off without any kind of cleaner/degreaser. Fingers crossed this doesnt happen again.

 

[Number4]

Nothing should come out of the vents. When it does it's almost always a sign of a bad heater core. The substance your are finding should be antifreeze. This also means you are breathing its fumes.

 

[D Hook]

During days of very high humidity, I've had condensation coming out of the vents when turning on the AC.

Having been in cars that had defective heater cores, you'd see other signs if that becomes a problem. Most noticeably, the odor.

 

[stonerhino]

Oddly enough, no odor inside.

I do smell a very faint coolant smell in the engine compartment, but no coolant loss.

 

[briwayjones]

A faint coolant smell is a normal thing even when the heater core is not bad. If the heater core is bad and it is throwing anti-freeze on the windshield it should be pretty noticeable.

 

[IIGood]

I just experienced something similar the other night. It was a bit on the colder side, and raining pretty good, so just a minute or two after getting in the Explorer (it had sat for a couple hours) the windows started to fog up.

I flipped the defroster on and set the temperature dial all the way up on the hot side...it cleared a small area just above the dash's defrost vent, but the rest of the windshield stayed fogged and never cleared itself. I had to clear it with a rag I had handy but it quickly fogged back up.

The HVAC system seems to be in proper working order otherwise...A/C works just fine, the heat works fine...just the defroster doesn't seem to be correct, at least not when it's cold AND rainy.

 

[Number4]

I just experienced something similar the other night. It was a bit on the colder side, and raining pretty good, so just a minute or two after getting in the Explorer (it had sat for a couple hours) the windows started to fog up.

I flipped the defroster on and set the temperature dial all the way up on the hot side...it cleared a small area just above the dash's defrost vent, but the rest of the windshield stayed fogged and never cleared itself. I had to clear it with a rag I had handy but it quickly fogged back up.

The HVAC system seems to be in proper working order otherwise...A/C works just fine, the heat works fine...just the defroster doesn't seem to be correct, at least not when it's cold AND rainy.

When your defrost is on, is any air coming out the front vents? Or, is there more air coming out the front vents than the defrost,

 

[IIGood]

When your defrost is on, is any air coming out the front vents? Or, is there more air coming out the front vents than the defrost,

I am fairly certain...about 99%...that there was no air coming out of the front vents. Just the ones on top of the dash (I do notice those vents seem rather small...I'd almost expect them to cover more area along the dash).

 

[Number4]

Most of what's behind the dash is ducting. Yet the airflow seems very week for the real estate it's been given.

 

[IIGood]

Most of what's behind the dash is ducting. Yet the airflow seems very week for the real estate it's been given.

So I've noticed. Even using the regular heat or A/C on full blast out the front vents seems pretty weak. And for having to cover such a large space...oh boy.

My Mustang's defrost clears fog up pretty quick, but then again, we're talking about a vehicle with a cabin area that's barely half the size of the Explorer.

Thanks...think I'll just have to chalk this up to the conditions that were present. Rain + cold = bad times for visibility in an SUV. LOL.

 

[D Hook]

I usually crack the front driver's and passenger side windows. Creates a little suction that pulls the air out of the vents better. Works for me anyway.

 

[IIGood]

Good idea; I'm sure I'll start doing that too once I get some of those side window visors...they're definitely on the list.

 

[briwayjones]

I have trouble believing that it is so poorly designed that it will only clear a hole above the defrost vents. The whole point of the defrost is to clear the whole windshield. Without being able to do that the defrost is pointless and it may as well not have one. The defrost on 2nd gens. (granted they are totally different vehicles) have no problem clearing the entire windshield.

I wonder if you have some kind of blend door problem?

 

[Number4]

On mine it's not a blend door problem but a selector door problem. No matter what I choose (defrost, vents, floor) it all comes out the front vents. I've yet to attempt a fix. Same issue in both my 05 and my 04.