Killer Defrost Problem

squakbox

Has anyone experienced killer defrost problem?

The first time it happened to me I was near the top of Snoqualmie Pass in a snowstorm in the left lane with other vehicles to my right. My quick judgement, apparently, at the time was that it was safest to try and maintain my position within my lane while simulatneously trying to clear the windshield. It only began to clear once I thought to lower a rear window.

The second time I was doing about 65 MPH on I5 in Tacoma southbound in the left lane with traffic all about. In that case I watched the nearby jersey barrier through the left window to maintain my lane position.

cml387

Never been on the Squonalmiewhatsit pass. Is that near Mallow?

CiniO

Could you explain what a "killer defrost problem" is?
I never heard such expression.
Google also seems to not be aware what is this.

Nissan doctor

Not a problem we'd be likely to have in our generally moderate climate I wouldn't think.

squakbox

My definition of Killer Defrost Problem

Almost all modern day (say 1985 and on) vehicles automatically activate the A/C in defrost/defog/demist mode. Once the A/C is used a thin film of moisture will always remain on the surfaces of the A/C evaporator, like a time bomb. The lower the ambient temperature is, the less efficient the A/C will be in "drying" that fresh incoming airflow, until at about 34F it's non-existant.

Anyone else experience this?

Cuddlesworth

Google has it as Washington. I wouldn't say we have ever had weather that was capable of freezing up a windscreen in a modern car with working heaters.

Mikko Mallikas

sweet Jesus !

Mikko Mallikas

Freezing fog by any chance?

CiniO

squakbox wrote: »

My definition of Killer Defrost Problem

Almost all modern day (say 1985 and on) vehicles automatically activate the A/C in defrost/defog/demist mode. Once the A/C is used a thin film of moisture will always remain on the surfaces of the A/C evaporator, like a time bomb. The lower the ambient temperature is, the less efficient the A/C will be in "drying" that fresh incoming airflow, until at about 34F it's non-existant.

Anyone else experience this?

Never experienced anything like that over last 13 years and over half a million kilometres of driving in different conditions.

squakbox

Driving through cold, damp air will cause moisture to condense on the windshield; it can also happen in warm, damp air, too.

Ronnie Beck

Warm humid air from a/c hits cold windscreen I think.

corktina

cml387 wrote: »

Never been on the Squonalmiewhatsit pass. Is that near Mallow?

no thats SquonalSie pass

Ronnie Beck

Mikko Mallikas wrote: »

Freezing fog by any chance?

Warm humid air from a/c hits cold windscreen I think.

Ronnie Beck

There predicting another bid freeze this year. I was driving back to galway in jan '11 on the m5 around moate. Hit the craziest fog at 70mph. Couldn't see the bonnet for about 50 metres.


http://www.stephenoconnor.info/about/latest-news/big-freeze-2012.html#.UJmSAYbmXIV

dgt

Apart from a very small misting when the car was damp I can't see anything more sinister being emitted from the heater in this climate!

Mycroft H

Ronnie Beck wrote: »

There predicting another bid freeze this year. I was driving back to galway in jan '11 on the m5 around moate. Hit the craziest fog at 70mph. Couldn't see the bonnet for about 50 metres.


http://www.stephenoconnor.info/about/latest-news/big-freeze-2012.html#.UJmSAYbmXIV

Air becomes super saturated at lower temperatures, so at lower temperatures fog forms really easy

ShanE90

squakbox wrote: »

My definition of Killer Defrost Problem

Almost all modern day (say 1985 and on) vehicles automatically activate the A/C in defrost/defog/demist mode. Once the A/C is used a thin film of moisture will always remain on the surfaces of the A/C evaporator, like a time bomb. The lower the ambient temperature is, the less efficient the A/C will be in "drying" that fresh incoming airflow, until at about 34F it's non-existant.

Anyone else experience this?

Most if not all vehicles with ac disengage the ac below ambient temperatures of about 3degC as it is too cold to produce any effective dehumidifying.

dondavenport

And it all happened on a September night...

What a tragedy

Cungi

In the big freeze of 2010/11, i was driving along the N7 in the left lane taking it handy, when a truck overtook me in the middle lane and splashed a load of water onto my windscreen. Which then froze instantly. Scary moment.

Stuck on quickclear and demisters and pulled over into the hard shoulder. Thank feck i had a bottle of salty water in the car.

CiniO

Cungi wrote: »

In the big freeze of 2010/11, i was driving along the N7 in the left lane taking it handy, when a truck overtook me in the middle lane and splashed a load of water onto my windscreen. Which then froze instantly. Scary moment.

Stuck on quickclear and demisters and pulled over into the hard shoulder. Thank feck i had a bottle of salty water in the car.

And then Yeti came out of shrubs and attacked you?

I can't believe people fell for that ? LOL

Cungi

CiniO wrote: »

And then Yeti came out of shrubs and attacked you?

3x Yeti and Santa Claus with an M16 assault rifle