The last two times I have driven at Interstate speeds into a strong, cold wind I have experienced a loss of cabin heat.
Once I get off the highway and slow down the heat starts pouring out. This is in temps below freezing.

What could be happening to me and my cold feet?

Thanks

__________________
John

1995 E320 - 115kmi+ Smoke Silver/Cream (Wife's Wagon)
1989 260E - 195kmi+ Black/Grey (My Panther)
1984 300D - 242kmi+ Black/Palomino (Retired)

I have the same problem in my 300SD. I think its called chill factor. The faster you go thru cold air more heat is lost, just as if you were standing in the wind you would feel colder compared to standing in still air.

P E H

Chill factor requires moisture to lose heat. No moisture, as on a car's metal, and no heat loss.

This leads me to conclude that your heater core is leaking slightly.

Just kidding - -

Ken300D

It could be a faulty thermostat. However, even with a good thermostat, very cold temperatures can hinder the engine from warming up. That's why you see the grill covers on school buses or trucks that can be adjusted to limit the amount of air flowing thru the radiator. I can remember driving across the Great plains some years ago in below 0 temperatures in the dead of winter. I knew my thermostat was good but I couldn't keep the coolant warm. I stopped at the first dumpster, picked up a piece of cardboard and blocked off about half the radiator. Presto! heat again.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sorry Ken, you are close,,, but no cigar... Chill factor does not require moisture... it only applies to warm bodied animals... it is the measure of the sweeping away of the insulating layer of air at the surface of the skin...thus it does not apply to trees, MB's, etc...
They simply have increased heat loss....

Well, I don't smoke much in the winter time anyway.

Maybe I can earn a cigar by the time it gets warm again. Nice to sit on the front porch and enjoy a good cigar.

Whatever it is, I'm feeling the chill factor today......

Ken300D

Ken300D,

You have the chill factor confused with the heat index.

Chill factor is moving air making it feel colder than it really is. I don't know the exact conversion numbers but an actual 32 F will feel something like 20 F with a 20 MPH wind. It has nothing to do with moisture. So a car going 60 MPH may experience a chill factor of 0 F at an actual air temp of 30 F.

Heat Index has to do with humidity (moisture) wheras 100 F at 50% relative himidity may feel like 115 F at 100% relative humidity. This is applicable to human skin only because of the evaparorative cooling our bodies use. Again, I don't know the exact conversion numbers.

P E H

Let me take a stab at this. I don't think a car ' experiences' anything but there is an effect of the 'chill factor' on the vehicle. I think a chunk of metal which is at 20 degrees in 20 degree temperature with no wind will still be at 20 degrees even when the wind is blowing 100 miles per hour. However, if that chunk of metal (an engine for instance) is producing heat at 20 degrees in no wind, it will take longer to dissipate that heat than if the wind is blowing at 100mph because the wind will carry away the heat faster. In other words, only bodies producing heat will be affected by the wind or 'chill factor' and what it affects is the speed at which the body will reach the ambient temperature.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I thought I should add that I see no noticeable difference on the temperature gauge during all of this.

Don't know if it matters or not....

__________________
John

1995 E320 - 115kmi+ Smoke Silver/Cream (Wife's Wagon)
1989 260E - 195kmi+ Black/Grey (My Panther)
1984 300D - 242kmi+ Black/Palomino (Retired)

Chill factor [and heat index] as applied to humans tries to take into account the effect of evaporative cooling on our skin, making the skin temp actually slightly cooler. In higher temperatures and humidiy, there is less evaporative cooling and our skin cannot cool us as well in lower humidity. Inanimate objects, like automobiles and dry thermometers do not experience wind chill. Wet bulb thermometers, with a wet wick placed on the bulb as the name implies, do experience this difference, and in fact are used for making two measurements of temperature to calculate relative humidity.

My guess is you have outside air leaking into the cabin, made worse at higher speeds, such that the heater either does not sense the cold, or cannot keep up. [My Suburban has an air leak on the passenger side the will freeze the passenger and the driver feels nothing!]

I'm assuming your engine coolant temperature gage doesn't show any loss of temp when this happens...

I believe inanimate objects can change as a result of the wind chill factor. For instance, there are kits available for motor homes which pump a spray of water onto the front of the radiator when the vehicle is climbing steep hills or driving in the desert. I think they work according to the chill factor. The water evaporating from the fins of the radiator cools the engine more than just dry air passing over the radiator. Wouldn't it then be reasonable to say that the engine is acting as if the outside temperature is 70 degrees whereas it is actually 100 degrees and this resultant change is a consequence of the wind chill factor??
And isn't any radiator itself an indication of the changes induced by wind speed? The more air flowing over the radiator fins, the cooler the radiator. Why shouldn't this be considered a wind chill factor?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

From the National Weather Service on wind chill:

1. What is wind chill temperature? back

A. The wind chill temperature is how cold people and animals feel when outside. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder. If the temperature is 0 degrees Fahrenheit and the wind is blowing at 15 mph, the wind chill is -19 degrees Fahrenheit. At this wind chill temperature, exposed skin can freeze in 30 minutes.

2. Can wind chill impact my car's radiator or exposed water pipe? back

A. The only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -5 degrees Fahrenheit and the wind chill temperature is -31 degrees Fahrenheit, then your car's radiator will not drop lower than -5 degrees Fahrenheit.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I think we should have put WIND CHILL into caps.. because it is a specific thing with an accepted definition... the wind can chill something... and faster the more of it... as several have pointed out.. but when used as " WIND CHILL " that means the definition which Kerry posted in paragraph A.

In flight school in Texas we were supposed to double time anytime we were outdoors...Except when the "wet bulb" temp got to a certain point and they raised the red flag... ( literally , they hoisted a red flag up the flag pole as the signal we could walk )...
This was a combination of the temperature and the humidity .... a heat index....this was when we were also 'breaking starch' twice a day ( putting on fresh clothes to try to look good all day...)... ugh...

jjalex,
wind chill or not, I'll bet on a torn monovalve diaphram.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

10-4 good buddy on the torn monovalve diaphram. Wind speed would necessarily have no effect on cabin warmth.

__________________
'96 C220 138,000mi, '95 E300D 239,000 mi., '87 300TD 214,000mi '88 6.2 Turbo Diesel Chevy Conversion Van 253,000 mi.