Warm up or no warm up?

[JTK]

Living in the Buffalo NY area all my life, I let the vehicle warm long enough to clean & safely see out the windows, then off I go. Long gone are the temperamental carbureted vehicles that you had to nurse along until they settled out. Now with gasoline at $2.60+ a gallon, there DEFINATELY wont be any excessive 'warming up' time.
G/luck
Joel

 

[davefr]

Simply not true. An unheated garage is actually heated from the ground which is like an giant heater that wants to stay at about a constant 50 degrees.

Even when its well below freezing outside my unheated garage rarely drops below about 35-40 degrees.

The exact temperature difference between outdoor ambient and garage ambient depends on lots of factors.

quote:

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Originally posted by obbop:
If the garage is not heated the vehicle will be the same temperature as the ambient air temperature.

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[labman]

I switched to backing in our first winter here in 1978. How many of you remember the severe winters we had in the late 70's? My driveway is straight, but over 100' long. That winter, it was a trench with white sides and bottom. Add trying to back through a white cloud of exhaust in the dark, and I couldn't see where I was going.

Even on a summer's day, from out on the street, I have a better view of traffic when I start to back in from the street than backing out. It is a lightly traveled residential street, and only has a limited number of morons that don't belong there, blasting through.

 

[XS650]

quote:

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Originally posted by obbop:
If the garage is not heated the vehicle will be the same temperature as the ambient air temperature.

Wind chill effect does not affect non-living tissue.

A wind can waft away heat faster than calm air but after a couple hours the ambient temp of the metal will be the same whether the vehicle is inside or outside.

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The temperature in my garage never drops below 50, even on the rare nights that it actually freeses here. The R18 walls and R30 ceiling probably help a bit.

Our garage in San Jose never dropped below 40F, even when it got down to the mid 20s the one night it did in the 30 years we lived there.

Engine temperatures also lag ambient air temperature by several hours.

 

[Tosh]

And I would also be very surprised if dew formed on a car parked in a garage.

 

[JAYCEE]

Don't warm up.

Just keep the RPMs down until the coolant temp guage comes up to operating temp.

 

[Gurkha]

quote:

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Originally posted by Ramblin Fever:

quote:

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Originally posted by Gurkha:
The best strategy is not to put undue load on the engine when it is cold, warm up actually is not advised by MB and others due to the fact that the engine gets carbon build up.

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Wondering if this is the reason for build up rather then what a lot of people think are oil viscosity / oil type issues.

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Actually on diesels, it needs heat on the head to do complete combustion, part of this theory also applies to gassers, one of the reason it is no good to idle for long.

 

[Eddie]

Wind chill does lower the temperature of materials. That is why brides freeze before roads because the wind evaporates moisture and causes a temperture drop.

 

[Ugly3]

quote:

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Originally posted by Eddie:
Wind chill does lower the temperature of materials. That is why brides freeze before roads because the wind evaporates moisture and causes a temperture drop.

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No, no, no. The bridges freeze first because they do not get the benefit of ground heat that the roads do. Wind chill has little to nothing to do with it.

 

[obbop]

Okay.......

Blowing on the surface of the hot drink.

Doing so does lower the temp a wee bit wuicker.

But, on inanimate objects moving atmosphere can not lower the temp below that of the ambient temperature.

Placing a warmed-up car/truck in a sheltered locale CAN slow the heat loss, slow the amount of time the warmed-up components reach the ambient air temperature. But, in a relatively short time the temps of a sheltered and unsheltered conveyance will both be at the ambient temperature.

And, the colder it is, the quicker the heat is lost.

 

[frank1]

I start the car, wait until the fast idle comes down (EFI), and drive away. Usually runs 30 seconds or so, then I drive slowly until it warms up. I just want to be sure that the oil, and tranny oil had some time to get to where it needs to be.

 

[Crashbox]

quote:

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Originally posted by Ugly3:

quote:

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Originally posted by Eddie:
Wind chill does lower the temperature of materials. That is why brides freeze before roads because the wind evaporates moisture and causes a temperture drop.

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No, no, no. The bridges freeze first because they do not get the benefit of ground heat that the roads do. Wind chill has little to nothing to do with it.

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Exactly. However, Eddie stated that 'brides' freeze before roads- I could elaborate on that but this IS a family-friendly board!

 

[MN Driver]

My plan in the winter is generally to start the car and if it needs to be defrosted/defogged then there really isn't much you can do to reduce the idle time, however if that isn't the case and it is below or near freezing temperature, then I will generally idle for one minute and drive off keeping it easy. I'm still not sure what I will be doing in the middle of the night when I get off work because the highway is about 2 minutes from the highway and it's a suicide ramp going onto a 55mph road(ramp without an extra lane, so when you hit the bottom you better have a spot to fit between cars.) It seems like it will be hard to get on it without giving it some gas. My only chance is to find another route... ...The search is on.

 

[trynew]

quote:

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A wind can waft away heat faster than calm air but after a couple hours the ambient temp of the metal will be the same whether the vehicle is inside or outside.

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quote:

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Placing a warmed-up car/truck in a sheltered locale CAN slow the heat loss, slow the amount of time the warmed-up components reach the ambient air temperature. But, in a relatively short time the temps of a sheltered and unsheltered conveyance will both be at the ambient temperature.

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I think you are ignoring the evidence of the responders who actually measure the temperature of their unheated garages in the winter and find them to be 20 or more degrees warmer than the outside temperatures.

The term "relatively short" is also not accurate. It will be many hours before all the engine parts reach the air temperature in an enclosed unheated area, less in the open air.

 

[Tosh]

quote:

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Originally posted by obbop:

But, on inanimate objects moving atmosphere can not lower the temp below that of the ambient temperature.

Placing a warmed-up car/truck in a sheltered locale CAN slow the heat loss, slow the amount of time the warmed-up components reach the ambient air temperature. But, in a relatively short time the temps of a sheltered and unsheltered conveyance will both be at the ambient temperature.

And, the colder it is, the quicker the heat is lost.

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Actually, an object can become colder than the ambient air temperature due to heat lost by radiation to the cold night sky. Ever seen frozen dew in the morning when the air temperature hasn't actually been at freezing temperatures? So when a car is shielded from the sky, it doesn't lose heat through radiation.

Sure, if a car is parked in a drafty garage which provides no insulation barrier, it will probably reach ambient temperature through convection before morning, but that sort of stretches the meaning of 'garage.'

[ August 26, 2005, 03:49 AM: Message edited by: Tosh ]

 

[mechtech]

Tosh - No, I haven't seen water freeze above it's freezing point.
Neither have you.

 

[Tosh]

From this website:
http://www.mathcad.com/library/LibraryContent/MathML/clearnightfrost.htm

"A common observation is the formation of frost on clear nights when the air temperature is substantially above freezing. Twice in temperate-climated Torrance, CA, I had solar panel water pipes freeze and burst on such nights."

Sorry the calcs couldn't be a bit less technical.

 

[Tosh]

http://www.gi.alaska.edu/ScienceForum/ASF8/819.html

"The official temperature, which is measured at about head height above the ground, can be several degrees warmer than the air temperature a few inches above the ground. Plant leaves can be colder yet, and on a very open, exposed site they can freeze while the air, even near the ground, stays above the freezing point."

Seems it's called a 'radiation frost.'

 

[V1]

It may also be partly due to evaporation of water, which is a cooling process. Dry air and even calm wind will accelerate evaporation. I don't think I've ever heard of heat loss from the sky, or water freezing above 0c.

But about warming up engines? I always do it for at least a minute on the first start of the day. Some piston aircraft manuals recommend running the engine for at least 30 sec in summer, and 1 min in winter before adding power. This is to allow oil to completely circulate. That would be my only concern.

A buddy of mine had a '99 Grand Am V6 that blew a head gasket at 80k miles. Summer or winter, he would start the car and take off before the RPM's even reached the top of the spike. I'm talking within 4 seconds! I warned him about that.

 

[MN Driver]

The gaskets in the Grand Am V6 aren't good in the first place, he was lucky to have 80k miles before a gasket blew. I wouldn't attribute taking off with a cold engine to his gasket failure, although it wouldn't be good for the engine either.