cold-idling to warm up your engine

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CarGuru > Technology > cold-idling to warm up your engine 21 March 2005 20:28:16

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cold-idling to warm up your engine
Old Wolf 16 March 2005 14:35:39
	I was rather surprised to see the following letter in a motoring magazine today (paraphrased, I don't have it with me): "I am amazed at the number of people who warm up their engine by idling it from cold. Warmth comes from two things: friction and combustion. The heat from combustion is easily dissipated by the cooling system at idle, so if the car warms up it must be from friction, which is actually damaging the engine. The friction comes from parts not adequately coated in oil after a cold start. High revving is required to spray the oil into all of the required places. Therefore the best thing to do is to start the engine and immediately drive heavily, quickly spreading the oil around and bringing it up to the correct operating temperature ASAP." Any thoughts? It seems like crap to me.
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Lawrence Glickman 16 March 2005 14:52:57 [ permanent link ]
	On 16 Mar 2005 02:35:39 -0800, "Old Wolf" <oldwolf@inspire.net.nz> wrote: I was rather surprised to see the following letter in a>motoring magazine today (paraphrased, I don't have it>with me):> "I am amazed at the number of people who warm up their> engine by idling it from cold. Warmth comes from two> things: friction and combustion. The heat from> combustion is easily dissipated by the cooling system> at idle, Not so. The coolant stays IN THE BLOCK until it is up to thermostatic temperature, at which time it goes into circulation for thermal stability. so if the car warms up it must be from> friction, which is actually damaging the engine. crap. It warms up from the heat of the cylinders combusting fuel/air mix. The friction comes from parts not adequately coated in> oil after a cold start. negligible High revving is required to> spray the oil into all of the required places. hi revving a car that doesn't have it's oil up to pressure will cause premature engine wear/failure Therefore the best thing to do is to start the engine> and immediately drive heavily, quickly spreading the oil> around and bringing it up to the correct operating> temperature ASAP."> Any thoughts? It seems like crap to me. What is a word for "worse than crap" Lg
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Thomas Schдfer 16 March 2005 15:28:46 [ permanent link ]
	"Old Wolf" wrote Therefore the best thing to do is to start the engine> and immediately drive ...> Any thoughts? It seems like crap to me. Shortened the message like indicated above, I could agree: start the engine and drive away. But much of the original message is misleading or errourness. Thomas
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Nate Nagel 16 March 2005 17:28:17 [ permanent link ]
	Lawrence Glickman wrote: On 16 Mar 2005 02:35:39 -0800, "Old Wolf" <oldwolf@inspire.net.nz>> wrote:> I was rather surprised to see the following letter in a>>motoring magazine today (paraphrased, I don't have it>>with me):>> "I am amazed at the number of people who warm up their>> engine by idling it from cold. Warmth comes from two>> things: friction and combustion. The heat from>> combustion is easily dissipated by the cooling system>> at idle,> Not so. The coolant stays IN THE BLOCK until it is up to thermostatic> temperature, at which time it goes into circulation for thermal> stability. True, however, the engine can dissipate the heat from idle quite well without a cooling system at all. Convection and radiation off the block and heads take care of most of the heat at idle. In most cars it will take quite a while idling from a cold start to bring the engine up to full temp. (note that it's still not a good idea to run an engine without water in it at all - the water does conduct the heat from the cylinders to the outside of the block much better than would air.) so if the car warms up it must be from>> friction, which is actually damaging the engine.> crap.> It warms up from the heat of the cylinders combusting fuel/air mix.> True! The friction comes from parts not adequately coated in>> oil after a cold start.> negligible> If you believe the studies, it's not negligible - supposedly most of the wear of internal engine components occurs during a cold start. High revving is required to>> spray the oil into all of the required places.> hi revving a car that doesn't have it's oil up to pressure will cause> premature engine wear/failure Not exactly correct - the oil will be up to pressure in a few seconds (if it's not, there's a serious problem) but the oil will be thick and cold and will not be flowing with the required volume for optimum lubrication until the engine is warmed up. Next time you start a cold engine, watch the oil pressure gauge - it's not unusual to see 60 PSI or more on a cold start at idle, when the same engine at operating temp might only generate 15-20 PSI at idle. Therefore the best thing to do is to start the engine>> and immediately drive heavily, quickly spreading the oil>> around and bringing it up to the correct operating>> temperature ASAP.">> Any thoughts? It seems like crap to me.> What is a word for "worse than crap"> Despite some factual errors, there's a grain of truth. Assuming the vehicle isn't so cold that the windows won't defrost probably the best thing to do would be to wait a few seconds for the engine to "come off the choke" (for an older carbureted engine) and then begin driving moderately until the engine is at full temp at which point you can drive normally. The reasoning behind that is that even if you warm the engine up to normal temp before moving off, you're still idling for a long time which a) isn't particularly good for the engine in and of itself, and isn't very good for the catalyst either if so equipped and b) does nothing to warm up the other moving parts of the vehicle such as transmission, U-joints, rear end, wheel bearings, etc. which can only be brought up to normal temp by driving. When the vehicle is truly cold, even the suspension needs to warm up, ever notice that a vehicle rides really rough for the first mile or so when it's really cold out? nate -- replace "fly" with "com" to reply. http://home.comcast.net/~njnagel
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Frank 16 March 2005 18:25:36 [ permanent link ]
	I'd agree with Nate. I, and probably most of us live where we can drive moderately for the first few miles. I just start the car, wait a moment for the revs to drop, ease it into gear and drive moderately for the few miles it takes me to get to the interstate. I've never had a car that I bought new start using oil before I sold it.
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William R. Watt 16 March 2005 18:31:22 [ permanent link ]
	The best way to warm up a cold engine is to plug in the block heater for 15-30 minutes before starting the car. It's obvious from the sound of the starting motor turing over the engine that a block heater warms it up. I count to 10 before putting the car in gear and driving it. The engine will run fast while cold anyway, and use a rich fuel mixture, something I don't know much about. As mentioned, idling an engine is not good for it. Parts need to be under load, ie driving. Otherwise they rattle around eventually doing damage. My owner's manual says never idle the engine for more than 30 minutes. I'd guess idling a cold engine would be worse than idling a warm engine. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-FreeNet email must have "notspam" in subject or it's returned
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Brian 16 March 2005 19:02:28 [ permanent link ]
	As far as I'm concerned, it's unsafe to drive a car in cold weather that isn't warm enough to properly defrost the windshield. I can't count the number of times that I've seen people pull out onto highways with the windshield so fogged up they are scraping frost off the inside even while they are merging into 50 mph traffic. If you need to use your windshield washer fluid, you need to know that it won't frost up on you. It takes my van 10 minutes to get this warm in below freezing temperatures. I run Mobil One oil so I'm doing everything possible to reduce startup wear, but frankly the safety issue far over-rides the wear issue. Brian "William R. Watt" <ag384@FreeNet.Carleton.CA> wrote in message news:d19fvq$725$1@theodyn.ncf.ca...> The best way to warm up a cold engine is to plug in the block heater for> 15-30 minutes before starting the car. It's obvious from the sound of the> starting motor turing over the engine that a block heater warms it up.> I count to 10 before putting the car in gear and driving it.> The engine will run fast while cold anyway, and use a rich fuel mixture,> something I don't know much about.> As mentioned, idling an engine is not good for it. Parts need to be under> load, ie driving. Otherwise they rattle around eventually doing damage. My> owner's manual says never idle the engine for more than 30 minutes. I'd> guess idling a cold engine would be worse than idling a warm engine.> --> ------------------------------------------------------------------------------> William R Watt National Capital FreeNet Ottawa's free community > network> homepage: www.ncf.ca/~ag384/top.htm> warning: non-FreeNet email must have "notspam" in subject or it's returned
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Rich 16 March 2005 22:42:48 [ permanent link ]
	this is the best way to do it. period
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Nate Nagel 17 March 2005 03:47:00 [ permanent link ]
	Oh, agreed. But barring that, I'd say drive it as soon as you're comfortably situated in the car, belted, radio adjusted, etc. nate Brian wrote: As far as I'm concerned, it's unsafe to drive a car in cold weather that > isn't warm enough to properly defrost the windshield. I can't count the > number of times that I've seen people pull out onto highways with the > windshield so fogged up they are scraping frost off the inside even while > they are merging into 50 mph traffic. If you need to use your windshield > washer fluid, you need to know that it won't frost up on you. It takes my > van 10 minutes to get this warm in below freezing temperatures. I run Mobil > One oil so I'm doing everything possible to reduce startup wear, but frankly > the safety issue far over-rides the wear issue.> Brian> "William R. Watt" <ag384@FreeNet.Carleton.CA> wrote in message > news:d19fvq$725$1@theodyn.ncf.ca...> The best way to warm up a cold engine is to plug in the block heater for>>15-30 minutes before starting the car. It's obvious from the sound of the>>starting motor turing over the engine that a block heater warms it up.>> I count to 10 before putting the car in gear and driving it.>> The engine will run fast while cold anyway, and use a rich fuel mixture,>>something I don't know much about.>> As mentioned, idling an engine is not good for it. Parts need to be under>>load, ie driving. Otherwise they rattle around eventually doing damage. My>>owner's manual says never idle the engine for more than 30 minutes. I'd>>guess idling a cold engine would be worse than idling a warm engine.>> -->>------------------------------------------------------------------------------>>William R Watt National Capital FreeNet Ottawa's free community >>network>>homepage: www.ncf.ca/~ag384/top.htm>>warning: non-FreeNet email must have "notspam" in subject or it's returned > -- replace "fly" with "com" to reply. http://home.comcast.net/~njnagel
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Y_p_w 17 March 2005 11:50:22 [ permanent link ]
	Frank wrote: I'd agree with Nate. I, and probably most of us live where we can> drive moderately for the first few miles. I just start the car, wait a> moment for the revs to drop, ease it into gear and drive moderately for> the few miles it takes me to get to the interstate. I've never had a> car that I bought new start using oil before I sold it. My basic problem is that I live on a hill. My current route to work includes going down a 20% grade, preferably in 2nd gear at about 3000 RPM, and I doubt it's wise to do so with a cold engine and cold oil. I believe the fuel may be cut off during that extended downhill, but the oil wouldn't be at an ideal temp. My other alternative is to ride the brakes all the way down in 3rd gear. Alternate routes include some steepish uphill climbs that don't lend to gentle driving, not to mention my driveway is pretty darn steep too. I let it warm up for maybe a minute, and the coolant temp gauge is near normal by the time I hit the steep grade. OTOH - from work is another matter. I let it idle for about 10 secs before taking off, it's flat to the freeway onramp, and the coolant is usually near normal operating temps by then with gentle driving. Add bumper to bumper traffic for about a mile, and there's plenty of time for my engine to warm up. OTOH - there are all the European car drivers I see jackrabbit accelerate after about only two blocks off a cold engine.
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Y_p_w 17 March 2005 12:09:10 [ permanent link ]
	William R. Watt wrote: The best way to warm up a cold engine is to plug in the block heater for> 15-30 minutes before starting the car. It's obvious from the sound of the> starting motor turing over the engine that a block heater warms it up. Most block heaters (let's say 400 W) will only get the coolant temps to maybe 140 В°F. However - I haven't heard of any considerations that a warmish engine block might result in the the residual oil film "washing down" a bit. I count to 10 before putting the car in gear and driving it. That's pretty much what I do if I know I have a relatively flat path to the freeway or next incline. The engine will run fast while cold anyway, and use a rich fuel mixture,> something I don't know much about.> As mentioned, idling an engine is not good for it. Parts need to be under> load, ie driving. Otherwise they rattle around eventually doing damage. My> owner's manual says never idle the engine for more than 30 minutes. I'd> guess idling a cold engine would be worse than idling a warm engine. There are tradeoffs to everything. There are some situations where it would be difficult to perform "gentle driving" and a few minutes of idling would be a better alternative. I don't have any way to gently drive my car from my driveway given the terrain where I live. Some days I'll just let the car idle for 1-2 minutes while I tie my shoelaces, etc.
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William R. Watt 17 March 2005 16:41:12 [ permanent link ]
	y_p_w (y_p_w@hotmail.com) writes: I don't have any way to gently drive my car from my driveway given the> terrain where I live. Some days I'll just let the car idle for 1-2> minutes while I tie my shoelaces, etc. I generally wait until I'm on the freeway and the engine is properly warmed up and I've drunk at least half my morning coffee before attempting to tie my shoelaces. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-FreeNet email must have "notspam" in subject or it's returned
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Robert Briggs 17 March 2005 22:02:32 [ permanent link ]
	Nate Nagel wrote:> Lawrence Glickman wrote: The coolant stays IN THE BLOCK until it is up to thermostatic> > temperature, at which time it goes into circulation for thermal> > stability.> True, however, the engine can dissipate the heat from idle quite> well without a cooling system at all. Really? Convection and radiation off the block and heads take care of most> of the heat at idle. In most cars it will take quite a while> idling from a cold start to bring the engine up to full temp. IME, engines tend to reach full temperature somewhat more easily while idling than during normal driving. This is certainly supported by the behaviour of the electric radiatior fans I have had over the years: run the engine at idle while working on the car, and in due course the fan cuts in; get stuck in traffic on a hot day, and the fan is very likely to cut in; maintain anything at all like a decent turn of speed, and the natural airflow through the radiator is quite enough to keep the fan off (except, perhaps, when there is a fault with the cooling system or when climbing an unusually steep hill).
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Lawrence Glickman 18 March 2005 01:32:07 [ permanent link ]
	On Thu, 17 Mar 2005 18:02:32 +0000, Robert Briggs <Trebor.Briggs@BITphysics.orgBUCKET> wrote: Nate Nagel wrote:>> Lawrence Glickman wrote:> The coolant stays IN THE BLOCK until it is up to thermostatic>> > temperature, at which time it goes into circulation for thermal>> > stability.>> True, however, the engine can dissipate the heat from idle quite>> well without a cooling system at all.> Really? I think our experiences differ in that we live in varying Climates. I have a full 4 Seasons up here at Lake Michigan, someone living in Canada is going to have a different experience than someone living in southern Texas. I remember a summer in Texas where I had to turn the engine on to cool the car down. It was so hot inside, I got a 2nd degree burn from the seat strap buckle ( metal ) and the steering wheel was too hot to touch. In that case, all you have to do is wait for the vehicle to cool off with air conditioning so you can get into it ;-\ My conclusion is these varying Climate conditions are what leads to the disagreements. In the Wintertime, I let my engine idle until I'm reasonably sure that the oil is thin enough to drive on. In summer, I'm waiting for the air conditioning to do its job. Any other time, it is just a matter of waiting for oil to be properly distributed to all the engine parts. This takes no more than maybe 30 seconds. As many have said, by the time you get your rear view mirror adjusted and the seat belt attached, you're ready to go, in =some= climates. Lg Convection and radiation off the block and heads take care of most>> of the heat at idle. In most cars it will take quite a while>> idling from a cold start to bring the engine up to full temp.> IME, engines tend to reach full temperature somewhat more easily>while idling than during normal driving.> This is certainly supported by the behaviour of the electric radiatior>fans I have had over the years: run the engine at idle while working>on the car, and in due course the fan cuts in; get stuck in traffic on>a hot day, and the fan is very likely to cut in; maintain anything at>all like a decent turn of speed, and the natural airflow through the>radiator is quite enough to keep the fan off (except, perhaps, when>there is a fault with the cooling system or when climbing an unusually>steep hill).
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Old Wolf 18 March 2005 07:59:43 [ permanent link ]
	Lawrence Glickman wrote:> It warms up from the heat of the cylinders combusting fuel/air mix.> How much of the heat comes from combustion, and how much from compression? I thought most of it was from compression (otherwise you wouldn't get the problem of detonation at higher compression ratios).
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Lawrence Glickman 18 March 2005 09:23:18 [ permanent link ]
	On 17 Mar 2005 19:59:43 -0800, "Old Wolf" <oldwolf@inspire.net.nz> wrote: Lawrence Glickman wrote:>> It warms up from the heat of the cylinders combusting fuel/air mix.>> How much of the heat comes from combustion, and how much from>compression?> I thought most of it was from compression (otherwise you>wouldn't get the problem of detonation at higher compression>ratios). In a gasoline engine. 9.7:1 compression ratio seems to be the magic number. Unless there is a hot spot on the cylinder head or piston, this wouldn't normally be enough to cause detonation of the fuel/air mix. Otoh, in DIESEL engines, compression IS brought up to a level that the friction of compaction exceeds the flash-off point ( ignition point ) of the fuel/air mix, and this is one of the differences between the two engines. Whereas: diesel relies on high compression, gasoline relies on external ignition source ( spark plug ). In order to contain these higher compression levels, diesel engines have a more robust design in general than gasoline engines. So in answer to your question "how much from compression" in diesel technology, ALL from compression to ignite fuel in gasoline technology, spark from ignition system. In a gasoline engine, running 3 liters up to 10 atmospheres is but a fractional amount of contribution to the heating of the engine if lubrication is not an issue. You can do this test in a lab, taking air sample temp at 14 psi ( 1 atmosphere ) and then again at 140 psi ( 10 atmospheres ) and measuring the caloric increase because of compression, but I don't think it is an "issue" in a street car. Lg
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Lawrence Glickman 19 March 2005 15:56:06 [ permanent link ]
	On 17 Mar 2005 19:59:43 -0800, "Old Wolf" <oldwolf@inspire.net.nz> wrote: Lawrence Glickman wrote:>> It warms up from the heat of the cylinders combusting fuel/air mix.>> How much of the heat comes from combustion, and how much from>compression?> I thought most of it was from compression (otherwise you>wouldn't get the problem of detonation at higher compression>ratios). //////////////////////////////////////////////////////////////////////////////////////////////////////////////////// ADDENDUM 3/19/2005 0600 hours Central Time ===================================== I would like to change what I said below. Now that I've given it more thought, my twin-cylinder air compressor is a well-lubricated assembly but produces enough heat from compression of air only to become too hot to touch. I haven't taken a reading of the cylinders yet after the machine has been running for a while, but there is a 3 horsepower electric motor attached to them, so a significant amount of WORK is being done in order to repeatedly bring 1 atmosphere up to just about what my automobile does in it's cylinders ( not including heat from combustion here ). I suspect the cylinder head on the air compressor becomes hot enough to boil water and then some, all from compressing AIR and possibly a little bit of friction thrown in there, but most likely the same amount of friction as found in my gasoline engine cylinders in my automobile. So I am retracting what I said about the heat from compression of AIR ALONE as being insignificant. I take it back. I hadn't thought "it" through enough when I made the statement below. Does it get hot enough to ignite any fuel/air mix at a 14.7air to 1 fuel ratio? I doubt it. Only hot enough to burn yourself on. If / when I get some temperature measurements, I'll post them here. The head is cooled by radiation ( fins ) and convection. Only the electric motor itself is cooled by a fan that turns with its arbor. In diesel, the compression can go up to 25:1, almost 3 times what is found in a gasoline engine ( typically around 9.7:1 ). Diesel IIRC runs anywhere between 14:1 to 25:1 depending on the engine. When a diesel engine is TDC or near it, fuel is introduced into the superheated air and that is when the fuel ignites, only because of the heat generated by compressing the air that much. My compressor takes air up to 120 psi, and by the time it has done that to the volume of compressed air that will fit into my holding tank, it is too hot to touch. So you have a valid point. But still, without a spark, a gasoline-powered engine isn't going anywhere except to a service bay ;) Lg ///////////////////////////////////////////////////////////////////////////////////////////////////////////////// In a gasoline engine. 9.7:1 compression ratio seems to be the magic number. Unless there is a hot spot on the cylinder head or piston, this wouldn't normally be enough to cause detonation of the fuel/air mix. Otoh, in DIESEL engines, compression IS brought up to a level that the friction of compaction exceeds the flash-off point ( ignition point ) of the fuel/air mix, and this is one of the differences between the two engines. Whereas: diesel relies on high compression, gasoline relies on external ignition source ( spark plug ). In order to contain these higher compression levels, diesel engines have a more robust design in general than gasoline engines. So in answer to your question "how much from compression" in diesel technology, ALL from compression to ignite fuel in gasoline technology, spark from ignition system. In a gasoline engine, running 3 liters up to 10 atmospheres is but a fractional amount of contribution to the heating of the engine if lubrication is not an issue. You can do this test in a lab, taking air sample temp at 14 psi ( 1 atmosphere ) and then again at 140 psi ( 10 atmospheres ) and measuring the caloric increase because of compression, but I don't think it is an "issue" in a street car. Lg
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JP White 19 March 2005 18:01:35 [ permanent link ]
	Steve wrote:> Well, the overall CONCLUSION is right, but the reasoning is BS.> You should start the car and then drive off (gently) rather than idle > for more than a minute or so, but its not because "the heat that warms > it up must come from friction" or because "the heat of combustion is > easily dissipated byu the cooling system." Its because extended idling > when cold unnecessarily dilutes the oil with combustion by-products, and > warms up the engine FAR more slowly than putting a light load on it as > soon as the oil pressure is stabilized after start-up (less than a > minute- more like 15-30 seconds).> This seems like the right tack IMO. I've always gone by the understanding that a cold idling engine will have more fuel entering the pot than can be burnt which gets past the piston rings. This leads to oil being stripped from the cylinder walls and fuel gets into the oil pan for a brief time. Gently drive away as soon as you start is my approach, and don't accelerate hard or drive at high speed until the engine temp is normal. JP -- JP White mailto:jpwhite3@bellsouth.net
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JP White 19 March 2005 19:10:11 [ permanent link ]
	Lawrence Glickman wrote: So you have a valid point. But still, without a spark, a> gasoline-powered engine isn't going anywhere except to a service bay> ;) You are correct, but I'd like to mention a special case. A hot and incorrectly timed gas engine may run on or 'diesel' after the ignition is turned off. If it won't stop by itself you may have to put it in gear to stop the engine rotation. So you are correct it's not going anywhere without a spark, but it may be capable of sucking your fuel tank dry without one. JP -- JP White mailto:jpwhite3@bellsouth.net
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Rich 19 March 2005 23:29:06 [ permanent link ]
	there is something most everybody is missing here... If you have an automatic trans, it runs it's fluid through the radiator in order to cool it. By idling your car for extended periods of time, you are buildong up heat in the trans that can cause damage in the long run. Trans fluid can only take so much heat before it starts to breakdown. The parts in your trans will soon follow.
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JazzMan 20 March 2005 00:45:03 [ permanent link ]
	rich wrote:> there is something most everybody is missing here...> If you have an automatic trans, it runs it's fluid through the radiator> in order to cool it.> By idling your car for extended periods of time, you are buildong up> heat in the trans that can cause damage in the long run.> Trans fluid can only take so much heat before it starts to breakdown.> The parts in your trans will soon follow. Actually, you've got it bass-ackwards. The tranny cooler's main function on cold startup is to warm the tranny fluid quickly using warm coolant in the radiator. Getting the tranny up to operating temps quickly greatly reduces wear and tear in the tranny. Once warmed up the tranny only puts heat back into the coolant when the vehicle is being driven hard or is pulling a load. With the torque converter locked trannies don't generate near as much heat as they used to. Idling for extended periods won't hurt the tranny at all. The thermostat sets the lower temperature limit of the coolant and the cooling fan activation temperature sets the upper limit. Those limits are typically 195В°F-230В°F, and the tranny is designed to operate happily in that range indefinitely. The only way the coolant temperature can go above that range is if there is a defect in the cooling system or a defect in the engine such as a blown head gasket. JazzMan -- ******************************************************** Please reply to jsavage"at"airmail.net. Curse those darned bulk e-mailers! ****************************************************** "Rats and roaches live by competition under the laws of supply and demand. It is the privilege of human beings to live under the laws of justice and mercy." - Wendell Berry ********************************************************
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Rudy Hiebert 20 March 2005 21:15:29 [ permanent link ]
	Not sure: 1.) where to put this post so I'm just jumping in here. 2.) what the reaction is to using synthetics but it's getting more logical to using this option. It's easy and simple to see how synthetics stay fluid in colder temps and lubes the insides of an engine quicker. Even in the heat of summer, it doesn't "cook off" as quick - it's volatility, making sludge a non-issue.
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Steve 21 March 2005 19:53:02 [ permanent link ]
	rich wrote: there is something most everybody is missing here...> If you have an automatic trans, it runs it's fluid through the radiator> in order to cool it.> By idling your car for extended periods of time, you are buildong up> heat in the trans that can cause damage in the long run.> Trans fluid can only take so much heat before it starts to breakdown.> The parts in your trans will soon follow.> 1) If you're idling the car in park or neutral, the transmission is not generating any substantial heat of its own because the clutches are all released and the input shaft is spinning freely. 2) If you're idling in gear, the torque convertor is generating a little bit of heat, but it should be within the capacity of the cooling system to get rid of it. 3) If the transmission IS generating enough heat at idle that it could be damaged, then its already ruined anyway and who cares? 4) As for the engine heating the transmisison fluid- unless the ENGINE overheats, the absolute hottest temperature that the transmission cooler will be exposed to is the thermostat temperature (usually around 180-210 degrees F), and realistically it will be lower because the trans cooler is usually (except for some particularly ignorant GM designs) located in the cool (return) radiator tank. Ergo- idling is NOT going to overheat or damage the transmission.
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Y_p_w 21 March 2005 20:28:16 [ permanent link ]
	Rudy Hiebert wrote:> Not sure:> 1.) where to put this post so I'm just jumping in here.> 2.) what the reaction is to using synthetics but it's getting more> logical to using this option. It's easy and simple to see how> synthetics stay fluid in colder temps and lubes the insides of an> engine quicker. Even in the heat of summer, it doesn't "cook off" as> quick - it's volatility, making sludge a non-issue. Well - another thing to factor is the blurring of the lines between what is a "synthetic oil" and what is a "conventional oil". These classificiations seem to be more a matter or marketing and product differentiation these days. About the only oil on most store shelves that I'm sure are "traditional" synthetics is Mobil 1. I know you're probably going to bring up Amsoil, but that's just not going to be an option for most people. In reading several MSDSs, it seemed like the big names (Pennzoil, Valvoline) are not selling the traditional PAO-based synthetics on the US markets - at least not all of them. Most conventional oils use "Group II" base oils, which do have lower volatility, better cold performance, and a higher inherent viscosity index. Pennzoil calls theirs "PureBase" while Chevron oils have the "IsoSyn" label. The Havoline bottle just say "group II". Check this out: <http://www.bobistheoilguy.com/oilbasics/ppframe.htm>
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CarGuru > Technology > cold-idling to warm up your engine 21 March 2005 20:28:16

	see also: Steering Column "birdcage'		pass tests:		see also: Ford KA hi!i here new regard.long ago there was not.

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cold-idling to warm up your engine

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