Hey all,

My 88 240 DL had frost on the inside of the windows for a 200 mile trip yesterday. I had the heat selector on #3 most of the time or until it got to warm inside and still the drivers side front and rear door had frost on them.

The frost was where the windows meet the top of the door, it was there the whole ride. I do have a little leak in the upper left hand corner of the window because it doesnt close all the way ( i think the tracks are shot) Could that be the cause?

Thanks in advance

Adrian

if you don't have one already, get a 197F/92C thermostat, which is
the correct stat for a non-turbo 240. A lot of people install colder
thermostats, and then complain when the heat is lukewarm - my car
"came" with an 82C stat - installing the correct thermostat made
a big difference in heat output and added a few MPG, too (hotter
engine is more efficient).

-b.

Adrian,
The heat is on high, the outside dash vent is open, fog/frost on the window is cleared by opening the driver side window 1/4 inch. Instant defogger.

Klaus
--
98 V70Rawd(101Kmi), 95 854T(85K mi), 88 245(165K mi)

hahahaa yeah, i tried that and it seemed to work pretty good until my sister started complaining (I was wearing a hat) :( I rolled it up and slowly it started to frost AGAIN. Oh well.

Adrian

frosted 240

yes, anod/or uppor part of dash vent not working thats whats suppose to clear side window

I must assume that the outside temp was below freezing.

Frost inside comes from the same thing as condensation on a cold drink glass. Common in the Houston, maybe not in your area.

Air has a certain amount of water vapor in it. How much is a function of the air temperature, warm air can hold more water vapor. It's a scientific fact that air at "X" temp can hold a max of "Y" water vapor. Relative humidity is the fraction of "Y" that the air has in it. If the vapor amount stays constant but the air temp drops, the relative humidity goes up. It cannot exceed 100%.

You may not notice the humidity in the car. But when that air touches cold, like the window, it gets chilled to the temp where it cannot hold the contained water vapor any more.

The vapor condenses as droplets, and if the cold surface is below freezing, the droplets can freeze on the surface.

So to stop the phenomenon you must reduce the relative humidity of the inside air. Several approaches. One is the leave the air control on outside air, as air drawn in will have low relative humidity once heated. Additional to that one can run the air conditioner, chilling the air further (maybe) and forcing more water vapor out of it.

It's either that or warm up the glass itself, which is practically impossible except for the rear window which has the electric strips.

If you experience inside fogging/frosting on the windshield, do the above especially running the a/c and the demist air setting.

Good Luck,

Bob

:>)
--
240s: 1986 244GL, 1988 244GL, and 5 others.

Yes, this is a common problem with the 240 and can come from many sources. The leak in the window may have allowed the water to build up inside the door and condense on the cold window near where the water vapor is rising. I often get this simply when water from boots or shoes are on the rubber mats in the front seats. I also had this happen when I had a small leak in the windshield gasket, and others have this happen when the heater core is leaking.
The bottom line is to use both A/C and heat, running through the front vents at the sides to point at the window (closing the center ones), or the defroster vents on, or both. Often this condition is worsened when you use the floor vents for heat becasue the water vapor temp is increased where the water resides and rises up to the windows.
The 240 is unique for a Volvo to use defrost, since it is a manual system and depends on the operator to select the A/C when it is needed to remove water vapor in the cabin. All other Volvos including 700/900 and later put the A/C on automatically to do this when the defroster position is selected. This is covered pretty well in the 240 owners manual.
--
'89 245 Sportwagon, '04 V70 2.5T Sportwagon

Hey guys,

I dont have air conditioning on the car. Any other ideas?

Ill take a look at the cold air vent though.

thanks for responding,

Adrian

Well, that's not good!
Hold your breath on those cold mornings so it won't fog!

Also, you may wnat to increase the temp rating of your thermostat so the engine gets warmer, giving better defrosting.
--
'89 245 Sportwagon, '04 V70 2.5T Sportwagon

I could do that, however, I just replaced the thermostat and did a coolant flush at school for credit. That was about 3 weeks ago.

Ill try holding my breath.......we'll see if that works ;)

Adrian

frosted 240

here's a little trick from the north. When the car is all warm after a drive, park it with a leeward (downwind) window open a 1/2 inch or so. The wind will pull all the warm (damp) air out of the car. Whne you get back to the car even on the coldest of days or nights there will be no frost condensated on the inside of the windows.

Trick #2: makes sure you have rubber carpet pads that collect water so that the carpets underneath aren,t wet all the time. Not only is this a huge source of moisture for the air in the car (the heating system makes the water vapourize as you warm you toes) it may also delay the onset of rust in the floor pans.
Trick# 3 use a piece of cardboard to partially block the rad up front, this will allow the engine to reach operating temp faster and on long highway trips will keep the cabin toasty....

WARNING!!! you must have a temp gage that works as in stop and go traffic or heavy climbing the engine might overheat!!!
That being said I watch the temp gage and have only had to get out and remove the cardboard once on a unseaonably warm day in Feb when i got stuck in a traffic jam on the highway.
--
Patrick, '68 220, '83 245, '92 Eurovan (work truck).