Re: can\'t see window still fogs up??

Anything that allows a good airflow into the heater system, is going to carry a little snow with it. But a little snow shouldn't cause much trouble once everything is warmed up.

Are you sure your heater core doesn't have a tiny leak? It doesn't take much to cause a lot of humidity in the heater box.

I might have been born at night, but it wasn't LAST night.

 

Re: can\'t see window still fogs up??

Again I follow Jim_Lou and he is right. Check the heater core and hoses. I bet it will be the heater core. They suck changing them but that most likely is your problem.

 

Re: can\'t see window still fogs up??

When my heater core blew "on my full sized GMC" the window fogged over right now. It should smell.

 

Re: can\'t see window still fogs up??

i replaced the heater core when i did the blower motor just to be safe ... I'll double check it ... shouldn't the frost have a tint and leave a film if its anti-freez? And it clears up after 1/4 mile or so? when the heater core on my plymouth went it never cleared up.

thanks

 

Re: can\'t see window still fogs up??

No, the frost won't be green because the antifreeze, and the dye that's in it, don't evaporate much. If the leak is bad it might smell, but a small leak can create humidity without a noticible smell.

If a heater core is your problem, it could be leaking while the system is pressurized after shutting the engine off. That can leave a puddle in the heater housing. When hot air starts blowing through the core, the puddle evaporates causing your fog. After a while the warm air dissipates the fog, and the leak is too small to sustain it on an ongoing basis.

Being a new core makes that scenario unlikely but not impossible. The only way to check it is to get the core exposed and then pressurize the system with a pump.

I'd try to eliminate the possibility of snow in the intake first. Just duct tape the opening over night, and then sweep all the snow off before uncovering the intake, and see what happens.

I might have been born at night, but it wasn't LAST night.

 

Re: can\'t see window still fogs up??

I've done all the upgrades (new heater core/Blazer motor) and still get some frosting in the morning. You're right, it seems to get worse when a fresh bunch of snow is sucked into the intake. The only real success I've ever had with this is to place a 1500 watt portable heater in the cab and preheat the interior for 15 to 30 minutes. Preheating the cab seems to get the heating system "over the hump" and it seems to do well from there. I've also been thinking about converting my AC into another heater, but haven't found the time to do that on this winter.

BTW: I doubt that the air dam thing would make the difference.

Good luck

 

Re: can\'t see window still fogs up??

In reply to:

... shouldn't the frost have a tint and leave a film if its anti-freez? And it clears up after 1/4 mile or so? when the heater core on my plymouth went it never cleared up.

1. A mist of engine coolant will have:
a. Anti-freeze smell.
b. Anti-freeze feel.
c. Won't clear up after 1/4 mile of use.
d. Will coat the glass and need to be cleaned off.

2. The problem is just localized humitidy not being baked out during the first use of the Jeep.

My guess is that the humidity in the box, coupled with any humidity taken in the fresh air vent (snow, rain, dead wet leaves, etc.) will also be sucked dry in no time by the input air flow. If the heater core ain't hot.. then it does not heat the in-coming air and the humidity ain't baked out. Modern cars use the air conditioning system to dry all in-coming air.

 

Re: can\'t see window still fogs up??

Is plenty air blowing at the windshield? It is warm air?

If not, make it so... that air is what will keep the windshield clear. Rusty windshield frame will leak air. Bad defrost duct will leak air. Yes, the OE type defrost deflectors that attach to the windshield frame to make a difference - at least they do in my CJ.
Also I get better performance from my heat/defrost if I pull the vent lever open just slightly... to allow more air flow but not so much as to let in the cold air. You should be able to see the door open/close if you look down through the cowl vent.

If it is moving plenty air across the windshield... could be too wet just like the others said. Tons of snow in the fresh air vent will cause the air to be wet.

Is the problem with frost or fog? i.e. warm wet air will make fog where not much air or cold air will start as fog then freeze to be frost.

last but mostly least... I had a Jeep what would fog up bad real bad unless I opened one of the hard door vent windows just a bit... after that I had clear windows and toasty warm. Don't know how well your Jeep is sealed, but maybe not enough fresh air is allowed in.

 

Re: can\'t see window still fogs up??

I get plenty of air and its warm ... I looked after work and there was a couple of drops under the heater box but it was water not anti-freeze. I have a soft top but its sealed up pretty good. I leave the vent open a little too (other wise the air flow sounds restricted). Its warm air that turns to frost. I'll try taping the fresh air vent tonight and see if that helps. Is there a good solution if it's the problem?

Thanks for the info

 

Re: can\'t see window still fogs up??

I started to drive through the Columbia River Gorge (East out of Portland, Oregon) one day in a major snow storm in my 72 CJ5. Defroster was on full tilt; scraper in my right hand removing ice from the inside of the windshield as fast as I could. I gave up and turned around when it seemed like it was snowing inside the jeep as fast as it was outside the Jeep. I didn't want to go to work that bad anyway.

Good Luck!
Kriss

 

Re: can\'t see window still fogs up??

I taped off the fresh air intake ... so no snow in the fresh air intake and no frost on the inside of the window ... Any ideas besides taping it every nigth?

 

Re: can\'t see window still fogs up??

On eBay, I've seen a magnetic cowl cover that should be easier than taping the intake every night. Apparently, there's a large enough demand for these things that somebody came up with a product.

Do a search on ebaymotors.com and you should find one within a week or two. Otherwise, try to find a large flat magnet elsewhere, that's all you need.

TEXAS1AL

84 CJ-7; 258 I6; Restored-to-Stock Condition, TR Ignition Upgrade

 

Re: can\'t see window still fogs up??

You could remove the vent box on the passenger side over the fan inlet. It is the connection from the fresh air box to the fan. You will re-circulate the air inside the Jeep keeping it warmer and still be able to get fresh air when you desire. Mine's been off since I put the 'glass body on nearly ten years ago.

I've replaced so many parts that my old Jeep has become my new Jeep.

 

Re: can\'t see window still fogs up??

Try something heavy enough to not be blown away.
Maybe goto a magnetic sign company and buy a piece of material or 'some scrap' big enough to cover the vent.
Cowl vent covers http://www.quadratec.com/cgi-bin/sgin0101.exe?UID=2002030712131840&T1=13006+12&UREQA=1&UREQB=2&UREQC=3&UREQD=4&FNM=12&x=35&y=46 are available from :
Quadratec - http://www.quadratec.com/
4 Wheel Parts Wholesalers - http://www.4wheelparts.com/
J C Whitney - http://www.jcwhitney.com/
Probably your local 4x4 shop too...

Maybe sleep on the hood /wwwthreads_images/icons/smile.gif

 

Re: can\'t see window still fogs up??

thanks for the ideas ... I think i'll order up a vent cover and put some screen or something in it and try the remove the vent box trick and see what happens. we're getting a bounch of snow as we speek ... the ride home will be fun.

 

Re: can\'t see window still fogs up??

Just a random idea.. What if you run a dehumidifier (like what they use to store RV's) overnight? I have not tried the anti-fog stuff (Same as the RainX) but it might be worth a shot. Some sort of drain cock at the bottom of the heater housing?

Scott
'85 CJ7 T.H.O.R.

 

Re: can\'t see window still fogs up??

i thought there was a drain hole? on the passenger side? it goes threw the fire wall right?

 

Re: can\'t see window still fogs up??

Have you cleared the drains? There is one for the fresh air box, about 1-1/4' diameter, and another for the heater box about 1/2". They both come through the firewall on the passenger side.

I've replaced so many parts that my old Jeep has become my new Jeep.

 

Re: can\'t see window still fogs up??

when I did the blower motor swap i cleaned it all up but I don't remember if I cleaned the tubes on the end ... I found a 2x6 works well to cover the vent up