Heated Water Jets

On my 1999 1.8LX they are on all the time with the ignition. They are not very effective, screen adative is required in winter to stop the screen washers from not working due to the water freezing up somewhere in the system.

Hi they are not made to heat the whole water comming through, they are made to prevent the jets itself from freezing and therefore be blocked. I don´t think that is realy necessary (spelled right?). bye Jupp

Of course you need screen washer fluid additives in freezing temperatures, but they vaporise faster than water and leaves pure water in the last mm of the nozzles, enough to freeze and jam the orifice. /per

"Mike" skrev i meddelandet news:cq78n7$klk$ snipped-for-privacy@sparta.btinternet.com...

The tank and motor and pipework still freeze up due to the wind chill even with fairly strong screen wash. -6 deg C here yesterday.

Tim..

No it will not, wind chill will only has the effect that it feels colder, it will not lower the actual temperature and therfore things can´t freeze when air temp is over the freezing point no matter how much wind it is. The reason why people feel colder when it´s windy is because the air next to the body (which is heated) vents off faster in wind and the body has to warm up more air.

Yep, this is correct. Windchill is something that people feel, inanimate objects don't experience it.

What sort of cheap screen wash are you using that freezes at -6C? The stuff we get here is good to about -30C at least. I've never had the spray jets on any car freeze up due to the screen wash freezing, but I have had them freeze due to snow and ice buildup that totally encased them in ice.

Here in Canada we can get -45°c windshield washer fluid and have never had a water jet clog to date. This past week we experienced temps as low as -37°c

Mike.

"Mark Olson" wrote

This is technically correct, but wind can affect vehicles in cold temperatures. It can pull away the heat of an warm engine faster, which can have an impact when parked for medium-term periods i.e. a couple of hours shopping or visiting. Plus, it can draw away the heat of a block heater plugged in over-night. I always try to park with the nose of the car away from the wind in either situation.

All good points.

As a practical matter, if you park outdoors for 8 hours or more without a block heater, it won't matter one bit whether the wind is calm or fierce, or what direction your car is facing, your car's engine will be just as cold.

My recall of O level physics isn't what it was, but I think heat can be transferred from a hot body by radiation, conduction and convection (if in a fluid such as air) and if that air is being moved forcibly accross a heated surface isn't that a heat transfer fluid ? so I think the temperature will fall more quickly than otherwise. Also there used to be a thing called "cooling by evaporation" where a wet surface would be cooled as the water on it evaporated under forced ventilation. So I think "wind chill" is a real physical effect not just something people feel. Meteorologists measure temperatures using thermometers that are shielded against the the wind hence the confusion IMHO.

That is true and is why I said "All good points" above.

Yes, I was aware of the physiological basis for windchill, which is why I said it was something that people feel. Remember, most cars and most thermometers don't sweat... YMMV.

Yes, it is a real physical effect in the sense that a body, human or not, has a harder job keeping warm when it is windy than when it´s calm but my point was that the body never gets any cooler than the air surrounding it. If the air temperature is over the freezing point then the washer fluid will not freeze even in full storm. If it is just a degree below freezing point it will freeze regardless of windspeed unless You add anti-freezing stuff.

The _rate_ of cooling can be affected by energy transfers (such as forcible matter exchange and matter change-of-state), but the absolute temperature of the system would indicate that the end state of any small part of the much-larger "closed system" (for this example, an area affected by cold weather) would not drop below the net temperature as indicated by the energy contained in that system. A car parked in an area with a weather temperature of -20°C and no wind will get just as cold as a car parked in weather of -20°C and high winds - that is, they'll both reach -20°C, but the second one will get there faster.

Unless my memory of p-chem is way off and I'm just talking out of my backside, which is always a possibility. :P