[sonick]

Edit: I may have caused some confusion with throwing in "Cold weather". In retrospect, more accurately what I'm trying to say is to "not warm up the engine by idling regardless of temperature."

I'm not talking about warming up the car's interior or defrosting the windows, but the actual warming up of the engine, engine fluids and drivetrain.

Original post:

Not sure if this is common knowledge for those who know about cars, but in case there's some people out there who don't know about this...

Since the weather is getting colder, I've noticed my neighbours and friends "warming up" their engines and cooling system by idling in their driveway for 5 to 10 minutes before driving away.

Although they have good intentions and think this is good for the engine, in actuality it is NOT. Warming up the engine by idling is bad as it merely warms up specific parts of the engine and not the entire engine and all it's components (bearings, transmission, differential).

It can also cause unnecessary excessive wear to the engine block as moisture condenses in the cylinders instead of evaporating/burning off due to the temperature mis-match.

The best way to start your engines is to let it run in idle for 30 seconds to 1 minute to get the oil pressure up and flowing, then drive gently; i.e. keep it in the low RPMs. Once the water temp hits normal, THEN drive normally.

Personally, I wait a few more minutes after the water temp hits operating range before pushing it, to ensure oil temperature is also in operating range.

[TheSalesman]

Well sometimes i HAVE to idle it for a few minutes because my windows are all frosted. If the windows arn't frosted up, i just start it and go right away.

[!Yaminashi]

Well sometimes i HAVE to idle it for a few minutes because my windows are all frosted. If the windows arn't frosted up, i just start it and go right away.

You could get out and scrape the frost off?

[Gh0stRider]

You could get out and scrape the frost off?

That is unheard of!

[roastpuff]

You could get out and scrape the frost off?

That is unheard of!

I bought my friend an ice scraper/snow brush, because he didn't have one and would have to wait for his windows to clear before driving.

He was very happy with the present. :thumbsup:

[TheSalesman]

its too cold outside!

[!Aznboi128]

I start it with my compustar pro, get to my car within a min and then drive off. Works wellas the heated seats get some time to warm before I climb in.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[GLOW]

You could get out and scrape the frost off?

after i scrape it off, the windows start to fog up, so i still need time it to clear up or else i'd be driving blind. i've seen ppl do that before on their old cars. practically have to stick their head out their window like a dog to see lol

[TheSalesman]

after i scrape it off, the windows start to fog up, so i still need time it to clear up or else i'd be driving blind. i've seen ppl do that before on their old cars. practically have to stick their head out their window like a dog to see lol

that also happens to me.

[Mugen EvOlutioN]

auto start for the win

[shenmecar]

My clutch releases slower when its cold.

[vexor]

I let it warm up until the rpms drop from 1500 to about 900 just after starting it... usually happens within 2 minutes

[ilvtofu]

I'm just wondering if warming up your car by idling is actually bad if your only intention is to warm up the interior of the car ie. butt warmers,defrost etc.

If you warm up the interior and then drive away after say 2 or 3 mins like a REGULAR person wouldn't that not cause any more damage than not idling the car for 2 or 3 mins?

[sonick]

I'm just wondering if warming up your car by idling is actually bad if your only intention is to warm up the interior of the car ie. butt warmers,defrost etc.

If you warm up the interior and then drive away after say 2 or 3 mins like a REGULAR person wouldn't that not cause any more damage than not idling the car for 2 or 3 mins?

If the engine is not warm how would the interior be warm?
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[AVS_Racing]

meh thats what auto starts for

[PiuYi]

My clutch releases slower when its cold.

same... i dont kno if its releasing slower or whatever but it feels different when its cold vs. after 10min of driving
anyone kno y?

[jeff_alexander]

My gearbox is clunky when it's cold, doesn't like to go into gear, after 15 minutes of driving, it becomes much more smoother.

[Gh0stRider]

i usually warm up for 1-2 mins before driving off.

could always put something on your windshield to prevent it from frosting up. I've seen some people use cardboard.

[!SG]

yup, i autostart for a few minutes, then hop in the car, and drive off slowly.

its not like i idle for a few minutes then race off!

[ilvtofu]

If the engine is not warm how would the interior be warm?
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

I don't know what car you drive but my engine does warm up when I idle in the morning because it is moving...

[!Yaminashi]

after i scrape it off, the windows start to fog up, so i still need time it to clear up or else i'd be driving blind. i've seen ppl do that before on their old cars. practically have to stick their head out their window like a dog to see lol

Your windows would surely defog before all the frost on your windows melts off
It takes all of 10 seconds to scrape your front window, right?

Wow you guys are lazy:p

[1exotic]

I'm sure its tempting for people with Turbo/BOV not to rev to hear that shit spoolz'

http://www.youtube.com/watch?v=Ffj01k64AZI

http://www.youtube.com/watch?v=HblCEQXQ8Q4&feature=related

[hk20000]

^ if you OWN that car you'll get bored very soon.

[Lomac]

I don't know what car you drive but my engine does warm up when I idle in the morning because it is moving...

Yes... but because the RPM's are merely in the 900-1500 rpm range, it takes faaaaaaaaaaar longer for the engine to warm up than if the car was actually driving down the road. As such, physically driving the car warms up the interior much faster than just idling.

[Eff-1]

lol I remember a few years back, i'd walk out, start the engine, crank up the heater/defrost, and go back inside. come back out 5 mins later, jump in and drive off. windows are defrosted and car is warm inside.

[ilvtofu]

Yes... but because the RPM's are merely in the 900-1500 rpm range, it takes faaaaaaaaaaar longer for the engine to warm up than if the car was actually driving down the road. As such, physically driving the car warms up the interior much faster than just idling.

Eff-1 pretty much said it for me :D

[!Yaminashi]

I think that surge sound would get annoying

[Lomac]

Eff-1 pretty much said it for me :D

The point, though, is that it's bad for the drivetrain when you do it.

[orange7]

shit.. I've been idling my car from cold starts for 2-5 mins, depending on my schedule, since it was new.

err... should I check if anything is damaged? If so, what should I check for?

[Gh0stRider]

.

its not like i idle for a few minutes then race off!

why not???? :D

[JordanLee]

Cardboard and or isopropyl alcohol works wonders.

[roastpuff]

Heated windshield wiper nozzles ftw!

[Benz_05TSX]

I have always wondered that problem too, so I idle for only 1 min....and I am cheap, don't wanna waste gas! hahahahahahahaha

[jlenko]

Here's a PSA for you: No one fucking cares.

BTW, there's a neat product by Rain X called De-Icer: http://www.rainx.com/Products/Windshield_Treatment/De-Icer.aspx, for all you lazy buggers that don't want to scrape. It works fucking amazing!! Windows clear in no time at all.

PS. Yes, I'm a lazy bugger too.

[GabAlmighty]

I idle my car for 5-10 minutes before I drive off in the morning. I'll let you guys know when the engine quits on me.


same... i dont kno if its releasing slower or whatever
but it feels different when its cold vs. after 10min of driving
anyone kno y?
Hydraulic clutch you have? Hydraulic fluid is thicker when cold.
I think that surge sound would get annoying
I got compressor surge around 200km/h in my old car, obviously driving those speeds on public roads with other traffic.

[RonaldTypeR]

Weird, I've been doing this method for almost 10 years every winter, and nothing ever seems to go wrong?

I guess for those who parked their cars in a heated garage, it's easy to say..My cars are parked out in the driveway, and some winter mornings, every single window would be frozen..The inside of the car gets so cold that my water bottle in the car would've been frozen solid..Even if I scrape the ice off the windows, the inside would still be all fogged up..

So I just turn on my car, turn on the rear window defroster, crank up the heater and leave it running for about 10mins, or until everything melts AND defrosted, and the whole car gets warmed up (inside, outside, engine temp)...Again, I've been doing this for almost 10 years, my cars have 200,000+kms (my DD is actually 401,000kms), and nothing has ever gone wrong? Mind you, I also don't race off as soon as I leave the driveway..I usually drive my cars nice and easy (below 3000RPM) for at least another 10mins or so before I do my 'regular' driving :)

Anyways, just speaking from my own experience, and people I know who also do the same thing and never have any mechanical problem with their cars :thumbsup:

Ronald

[GabAlmighty]

Woot^^ real world experience :)

[sonick]

You guys are missing my point. The fact of the matter is that it is better for your engine if you warm it up by light driving, rather than idling at 900 rpm for five minutes.

Remote start is good and dandy but it is still not good for the engine to warm up to operating temp via idling in your driveway.

Of course if it is a matter of safety to let the windows defrost then by all means do so as effects are likely minor when done on occasion, but where possible its ultimately better to just drivethan to idle. Plus, I'm sure there's plenty of ppl who have done this all along with no issue.

As for the naysayers, go ahead and keep doing what you do, but if you care about your car, and would rather get a head start on your commute, I dont see a downside in what I'm suggesting.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)

[twitchyzero]

when snow melts early evening and freezes over during early morning then you simply can't just scrape it off.

that's why my dad installed the warm water nozzles with the windsheild wiper..works wonders

[3seriesBeeM]

compustar ftw i get in my car and its nice and toasty and defogged

[spoon.ek9]

my DD is parked outside and this is what i've been doing lately:

1. start up engine let it run about 15-30 seconds (which is at 1500rpm not 900rpm)
2. keep revs constant at 2000 rpm for 60 seconds
3. drive slowly until temperature is normal
4. then i turn the heater on (the engine is very sensitive to having the heater on, slows the warming up by a lot)

only extra idling is for when i have to scrape ice off the windows or wait for some fog to clear up. also, i find the gears grind easily when it's cold (especially in reverse) so i shift from 1st - 2nd - 3rd - 4th - 5th - jiggle - reverse. that seems to be the only way to not grind it.

[GabAlmighty]

You guys are missing my point. The fact of the matter is that it is better for your engine if you warm it up by light driving, rather than idling at 900 rpm for five minutes.
Posted via RS Mobile (http://www.revscene.net/forums/announcement.php?a=228)
I think my cold idle is around 1100 rpm, so is my warm idle. I care about my car, do not assume I don't.

[!SG]

yes yes,

if u are warming up the car, all u are warming up is the engine, not the drive train.

so thus, if u do warm up ur car for a bit, you should still drive slow for the first bit so that the fluids in the drive train circulate + have a chance to warm up a bit.

my car idles at like 1800 rpm if the engine is cold. it actually goes thru different stages, 1800 dead cold, 1200 after a couple minutes, then 800-1000 as it creeps up to normal running temperature.

I changed my rear diff to a gl5 synthetic fluid. feels sluggish at cold temps which is fine by me because that feel reminds me the car is still too cold to drive at normal driving...

[RabidRat]

4. then i turn the heater on (the engine is very sensitive to having the heater on, slows the warming up by a lot)

huh. seriously? didn't know this.

[Leopold Stotch]

i read in my mom's owner's manual that driving at lower rpm in higher gears will help the engine warm up quicker.

[notching]

cold idles actually puts the engine in greater stress as opposed to just driving off
i usually idle for 10 seconds to let the oil circulated then drive lightly

[hk20000]

huh. seriously? didn't know this.

True for Toyotas.

Not true for Mitsubishi (there are NO water valves in the system)

I think not true for Hondas as well, what you want to check is if there's a water valve where your heater system connects to your engine. Some cars change the interior temp by letting hot water into the heater core some just change the amount of ventilation that actually goes through the core.

[Mugen EvOlutioN]

i read in my mom's owner's manual that driving at lower rpm in higher gears will help the engine warm up quicker.

yes it warms up faster becuz of higher rpm, but because every component in the car is still not up to normal operating temp, thus you can do more damage than good. When your car is ice cold, you wonna be as gentle to the throttle as possible, higher rpm = faster warm up because your piston now has to go up and down thousands of times per minute faster if u dont keep ur revs down, and the higher you rev the chance of your oil not doing its lubricating job when its cold.

[Great68]

slows the warming up by a lot)



Depends on where the heater core is supplied from. If it's from the engine side of the thermostat then yes. If it's from the radiator side of the T-stat, then no.

[sonick]

I may have caused some confusion with throwing in "Cold weather". More accurately would be saying to "not warm up the engine by idling regardless of temperature."

I'm not talking about warming up the car's interior or defrosting the windows, but the actual warming up of the engine, engine fluids and drivetrain.

[shenmecar]

yes it warms up faster becuz of higher rpm, but because every component in the car is still not up to normal operating temp, thus you can do more damage than good. When your car is ice cold, you wonna be as gentle to the throttle as possible, higher rpm = faster warm up because your piston now has to go up and down thousands of times per minute faster if u dont keep ur revs down, and the higher you rev the chance of your oil not doing its lubricating job when its cold.

No he said LOWER rpm in a HIGHER gear.

[Dinan3]

For my S2k, I'm told by our Tech who drives the same car to idle it to "2 bars" then drive off slowly.

[Mugen EvOlutioN]

No he said LOWER rpm in a HIGHER gear.

my bad , read it the opposite

[91civicZC]

Can you explain this all in more detail, or point to where this information is coming from? I think I must be missing something here as this doesn’t make any sense to me at all.

1)The idea that condensation builds and then somehow lingers in the cylinders, despite the explosions of air and gas, the heat from the friction of pistons moving at 1k+ rpm and the spent mix being pushed out of the cylinder when the valve opens, is something I am having a hard time with. If the motor is running correctly, any condensation that actually manages to find its way into the cylinders would be expelled almost immediately. I have seen heads get horribly pitted due to people spraying massive amounts of water into the cylinders “for performance cooling”. However this is not nearly the same, and the fractional amount of water that may have found its way into the cylinders during sitting would be expelled so quickly it really shouldn’t matter. How idling would prevent this I don’t understand.

2)Anything rotating will warm up, not to mention the coolant and oil being able to circulate for a while before taking off. I understand that driving will warm this up faster, but I am still missing how warming the car up can do any damage in the first place.

The ONLY downside I can see to warming a car up is waste of gas and the effect on the environment. Both things we need to consider, but I cant get my head around this causing any type of damage to the motor.

Please explain in more detail!

[slammer111]

Why people still do this archaic practice is completely beyond me. 2 mins a day for 4 months out of the year = 3h of idling, or about half a tank of gas. Then people do this again after they go for lunch, get off work, after dinner, after the movie.. what a waste of gas. :rolleyes:

This isn't 1970, guys.

http://oee.nrcan.gc.ca/transportation/idling/facts.cfm?attr=8

Ready to Use Facts

1. Idling gets you nowhere – and it can be costly. Excessive idling wastes a significant amount of fuel and money and generates needless greenhouse gas (GHG) emissions. If drivers of light-duty vehicles avoided idling by just three minutes a day, over the year Canadians would collectively save 630 million litres of fuel and 1.4 million tonnes of carbon dioxide (CO2) emissions, and $630 million in fuel costs (assuming a fuel cost of $1.00/L).
2. Warming up the vehicle means more than warming the engine. The tires, transmission, wheel bearings and other moving parts also need to be warmed up for the vehicle to perform well. Most of these parts don't begin to warm up until you drive the vehicle.
3. Any more than ten seconds of idling uses more fuel than is required to restart the engine. However, the break-even time to offset any potential incremental maintenance costs to the starter or battery is under 60 seconds. So, as a guideline, if you're stopped for more than 60 seconds – except in traffic – turn off the engine.
4. For the average vehicle with a 3-litre engine, every 10 minutes of idling costs over one quarter of a litre (over 1 cup) in wasted fuel. Keep in mind that every litre of gasoline you use produces about 2.3 kilograms of carbon dioxide.
5. If you're going to be stopped for more than 60 seconds – except in traffic – turn the engine off. Unnecessary idling wastes money and fuel, and produces greenhouse gases that contribute to climate change.
6. Contrary to popular belief, excessive idling is not an effective way to warm up your vehicle, even in cold weather. The best way to warm it up is to drive it. In fact, with today's computer-controlled engines, even on cold winter days, no more than two to three minutes of idling is usually enough warm-up time before starting to drive. This also reduces fuel consumption and GHG emissions.
7. You can help reduce the impact of cold starts – and reduce idling times – by using a block heater on cold winter days. This device warms the coolant, which in turn warms the engine block and lubricants. The engine will start more easily and reach its proper operating temperature faster.
8. You don't need to leave a block heater plugged in overnight to warm the engine – two hours is more than enough. In fact, you can use an automatic timer to switch on the block heater two hours before you leave. At -20°C, block heaters can improve overall fuel economy by as much as 10 percent. For a single short trip at -25°C your fuel savings could be in the order of 25 percent.
9. A poorly-tuned engine uses up to 15 percent more energy when idling than a well-tuned engine. Keeping your vehicle properly maintained according to the manufacturer's suggested maintenance schedule is a key to fuel efficiency and reduced GHG emissions.
10. Calculations drawn from a 1998 survey on driving habits suggests that in the peak of winter, Canadians voluntarily idle their vehicles for a combined total of more than 75 million minutes a day – equal to one vehicle idling for 144 years. We idle about 40 percent less in summer, but Canadian motorists still waste a significant amount of fuel and emit unnecessary greenhouse gas emissions.
11. Warming up a vehicle in the winter and cooling it down in the summer are the most common reasons given for idling! Surveys show that Canadians also idle while waiting for passengers, stopping at railroad crossings, waiting to park, running quick errands, sitting in drive-through lanes and when stopping to talk to an acquaintance or friend.

I NEVER warm up my car, ever. Never have, never will. Just gotta scrape the exterior glass (I just do a "band" around my car at eye level, I'm lazy ;)) and keep a rag inside the glove box to wipe the inside of the windshield when it fogs up during the first minute or 2 of driving. And it's common sense to be gentle on your engine when it's not warmed up yet; anyone who's not a retard with cars would know that. Unless there's some regulation I don't know about that require people to WOT it out of their driveways and in their neighbourhoods.

:lol at people who don't know glass scrapers exist. I guess some people have never set foot inside a Canadian Tire?

[sonick]

snip

1. It's the prolonged time below operating temperature of the engine that causes issues of condensation. Once it's warmed up through either method, it is not a problem. Because it operates at lower-than-optimal temperature for a longer period of time, excess air in the combustion process cools the cylinder liners, resulting in incomplete combustion and condensation of unburned fuel on the cylinder walls. These deposits are eventually drawn into the engine sump where they contaminate the engine oil and reduce its effectiveness as a lubricant.

This is why it's it's common advice to change the oil more often during the winter than in summer.

2. The "damage" to the engine(I would more accurately describe it as excessive wear than 'damage') is from the info in point #1. However, other components may experience excessive wear as well if the driver drives as if the engine is warm, while all other components (hydraulic fluid, transmission fluid, differential fluid) are still cold. It would be redundant to idle-warm-up the engine for 5 minutes, only to drive gently for another 5 afterwards just to get the rest of the fluids up to temp.

[91civicZC]

I understand the theory then, not sure I buy it as factual. Do you have somewhere that’s done any testing on it that we could read up on?

[spoon.ek9]

huh. seriously? didn't know this.

True for Toyotas.

Not true for Mitsubishi (there are NO water valves in the system)

I think not true for Hondas as well, what you want to check is if there's a water valve where your heater system connects to your engine. Some cars change the interior temp by letting hot water into the heater core some just change the amount of ventilation that actually goes through the core.

my DD is a 1990 EF Dx, cable clutch and transmission. as for where the heater system connects, i don't know lol. all i know is, if i start the engine with the heat on full blast, it takes 3-5 minutes longer to warm up the engine (going by what it indicates on the cluster here) compared to when i leave it at cold. Also, if persay i turn the heater on before the engine has reached its normal running temp, the needle will go back down to cold on the cluster.

i have never seen that on any other car i've driven and i can't explain it; can someone here?

[Mugen EvOlutioN]

its ok half tank of gas wasted because of idling after 6 months is only $20 bux or so, for that i rather have my ass warmed up rather than freezing my balls off:D

[spoon.ek9]

i calculate my fuel mileage every tank of gas. i actually noticed it IMPROVED slightly rather than getting worse because of the extra idling time (6.93L/100km vs 7.00L/100km).

[GabAlmighty]

Ya, definitely notice my drive train when it's cold. 30 year old transmissions are a little sensitive, i take it easy when i drive off after warming the engine up. Usually don't' go past 3k or so.

[GabAlmighty]

i calculate my fuel mileage every tank of gas. i actually noticed it IMPROVED slightly rather than getting worse because of the extra idling time (6.93L/100km vs 7.00L/100km).
I would believe this. If I remember correctly on my old car if I drove it right away when it was cold I think the AFR's read really rich until it warmed up... and that car took a while to warm up.

[spoon.ek9]

^ me too, after the short idling period i still drive slowly until everything has warmed up correctly.

[slammer111]

its ok half tank of gas wasted because of idling after 6 months is only $20 bux or so, for that i rather have my ass warmed up rather than freezing my balls off:DExcept during the winter most people do the warmup thing a) several times during the day, and b) for a whole lot more than 2 minutes. That's a lot of bbt $ gone.

Oh, and warm balls = lower sperm count. ;) :D

[ronald55555]

1. It's the prolonged time below operating temperature of the engine that causes issues of condensation. Once it's warmed up through either method, it is not a problem. Because it operates at lower-than-optimal temperature for a longer period of time, excess air in the combustion process cools the cylinder liners, resulting in incomplete combustion and condensation of unburned fuel on the cylinder walls. These deposits are eventually drawn into the engine sump where they contaminate the engine oil and reduce its effectiveness as a lubricant.

This is why it's it's common advice to change the oil more often during the winter than in summer.

2. The "damage" to the engine(I would more accurately describe it as excessive wear than 'damage') is from the info in point #1. However, other components may experience excessive wear as well if the driver drives as if the engine is warm, while all other components (hydraulic fluid, transmission fluid, differential fluid) are still cold. It would be redundant to idle-warm-up the engine for 5 minutes, only to drive gently for another 5 afterwards just to get the rest of the fluids up to temp.

There seems to be no basis on the laws on physics and thermodynamics with those arguments, if there are, then please do explain further. I do agree that idling the engine does not warm up the transmission, and it requires driving the car to warm it up, that is a given. While i'm no expert in i.c. engines, those arguments do not support the theory that idling the engine prior to "warm up" causes damage to the engine with the mechanism you described. The adiabatic flame temperature of a combustion event is on the order of magnitude of thousands on degrees F. The combustion in an i.c. engine is far from ideal, it is not adiabatic, not complete combustion, and dissociation takes place, however, the temperature is still extremely high relative to the environment. The temperature will be what it is (depending on afr), whether the engine is warmed up will have minimal effect (relative to afr). I am not convinced the water will condense out of a vapour mixture onto a surface hotter than the mixture.

You also mentioned, and i quote "Because it operates at lower-than-optimal temperature for a longer period of time, excess air in the combustion process cools the cylinder liners, resulting in incomplete combustion and condensation of unburned fuel on the cylinder walls."

Where is this excess air coming from? Correct me if i'm wrong, but i believe most cars tend to run rich after a cold start. It it is running in closed loop, then it would be running at stoich. Even if it were true that the engine is running lean, that statement contradicts itself. Running lean will help the reaction of hydrocarbons going to carbon dioxide, with excess oxygen/nox.

[sonick]

^ Awesome post. If the actual technical facts or test are out there, I'd be interested in reading as well whether it confirms or debunks what I've been led to believe.

All my personal information from reading online from various non-scientific sources and hearsay from various mechanics and such where pretty much every instance says its better to not idle to operating temperature than to do so.

[ronald55555]

i read in my mom's owner's manual that driving at lower rpm in higher gears will help the engine warm up quicker.

I'm slightly skeptical about that. I'm not sure if it warms up faster or not, but low rpm/high load operations should generally be avoided. You want stable hydrodynamic lubrication for your crank bearings. ie the 2 metal surfaces with relative velocity with each other actually floats, and are not in direct contact. For this to happen, you need enough relative velocity(engine speed). The load also can not go above the point at which the file become unstable(throttle).

[91civicZC]

There seems to be no basis on the laws on physics and thermodynamics with those arguments, if there are, then please do explain further. I do agree that idling the engine does not warm up the transmission, and it requires driving the car to warm it up, that is a given. While i'm no expert in i.c. engines, those arguments do not support the theory that idling the engine prior to "warm up" causes damage to the engine with the mechanism you described. The adiabatic flame temperature of a combustion event is on the order of magnitude of thousands on degrees F. The combustion in an i.c. engine is far from ideal, it is not adiabatic, not complete combustion, and dissociation takes place, however, the temperature is still extremely high relative to the environment. The temperature will be what it is (depending on afr), whether the engine is warmed up will have minimal effect (relative to afr). I am not convinced the water will condense out of a vapour mixture onto a surface hotter than the mixture.

You also mentioned, and i quote "Because it operates at lower-than-optimal temperature for a longer period of time, excess air in the combustion process cools the cylinder liners, resulting in incomplete combustion and condensation of unburned fuel on the cylinder walls."

Where is this excess air coming from? Correct me if i'm wrong, but i believe most cars tend to run rich after a cold start. It it is running in closed loop, then it would be running at stoich. Even if it were true that the engine is running lean, that statement contradicts itself. Running lean will help the reaction of hydrocarbons going to carbon dioxide, with excess oxygen/nox.


I knew I wasn’t the only one who this seemed odd to.

I would say the people who have been saying this to you Sonick are either very confused, or are looking to try and have people cut down on idle time because of environmental concerns.If you are in conact with any of these folks who have told you this, try and get some actual reasoning out of them.

While I am all for cutting down on our environmental impact, I still dont think the argument being brought up with you is a factual one for causing engine damage. "Cold" is a reative term when it comes to temps inside a motor and cylinders.

[sonick]

I knew I wasn’t the only one who this seemed odd to.

I would say the people who have been saying this to you Sonick are either very confused, or are looking to try and have people cut down on idle time because of environmental concerns.If you are in conact with any of these folks who have told you this, try and get some actual reasoning out of them.

While I am all for cutting down on our environmental impact, I still dont think the argument being brought up with you is a factual one for causing engine damage. "Cold" is a reative term when it comes to temps inside a motor and cylinders.

True, perhaps the technical reasoning behind the actual excessive engine wear claims are sketchy, but overall I still believe the action of not idling to operating temp is still better than doing so because of the the warm-up of other components and such. Either way, I am interested in hearing about it if anybody finds any hard facts.

If there's technical information out there that suggests idling to temp is BETTER than not idling and driving gently, I'd be glad to hear it and apologize for giving bad advice.

Personally I really think about the environmental impact, just whatever is best for the car lol.

[LiquidTurbo]

The discussion in here is very interesting.

It'd be interesting to see a comparison of two cars over a lifetime, one always warmed up slowly, one driven right away, both driven similarly.

It's possible that there wouldn't be any difference in engine longevity at all, given the cold car wasn't redlined constantly, when completely cold.

[ronald55555]

You did bring up a valid point about warming up other components such as the drivetrain. A lot of people only warm up their engine, then proceed to driving the car normally. Personally, I warm up the engine by idling AND i take it easy once i start driving.

As for the environmental impact, and wallet impact, I think it's actually debatable. There's no doubt that idling the car results in an overall efficiency of 0%, or 0 mpg. But the efficiency of the engine itself is actually quite good, especially in newer cars. It consumes very little gas, and produce very little harmful gases. With that in mind, what if we look at the grand scheme of things. If a car was never allowed to warm up in its lifetime, maybe the engine will fail sooner compared to a car that had always been warmed up on a cold start. What is the total environmental impact of each car? Dos scrapping car A earlier (making the owner buy another car earlier), have a greater or less environmental impact than the total amount of time car B spent in idling? How does the amount of money needed to repair the engine in car A(or amount of money to buy a new car), compare to the extra gas bill that went into idling car B?

There are really no right answers to those questions, it depends on the car, and it depends on you ask. Just something to ponder about. On a side note, from manufacturing to scrapping, a Prius has about the same environmental impact as a Hummer. (quoted from an old professor/engineer, I can not confirm the validity of this statement) The point is, we have to think about the environment impact as a whole, not just at specific stages of a product's life.

[Inaii]

My car doesn't move unless it's been warmed up. The engine will stall continuously. Yay for old rotaries.

[Mugen EvOlutioN]

Except during the winter most people do the warmup thing a) several times during the day, and b) for a whole lot more than 2 minutes. That's a lot of bbt $ gone.

Oh, and warm balls = lower sperm count. ;) :D

lol freaking ED u sure knows a lot about sperm loss eh

:p;):haha::haha::haha::haha::thumbsup:

[slammer111]

lol freaking ED u sure knows a lot about sperm loss eh

:p;):haha::haha::haha::haha::thumbsup:You betcha. Why, you only know about sperm gain? ;) :p

[Mugen EvOlutioN]

:haha::haha::haha: lol wtf dude ahahaha

ic wat u did there


Siemens taught u about semens

[tofu1413]

hmm

my porsche 944 owner's manual gave similar advice to not let the car sit and "warm up"

you're supposed to start it, drive off and not push the car (rapid accel, deccel etc)

even they said it would cause "engine damage" hmm weird.

[crazyazn]

I always start it and wait for the revs to drop (from ~2k to ~1.5k) then i drive off slowly staying in low(er) revs

[danizer]

i think its better not to idle for 5-10 mins...
my instantaneous mileage when idling in the cold is like 2.0l/hr!!! holy shit!

[Lomac]

I'm slightly skeptical about that. I'm not sure if it warms up faster or not, but low rpm/high load operations should generally be avoided. You want stable hydrodynamic lubrication for your crank bearings. ie the 2 metal surfaces with relative velocity with each other actually floats, and are not in direct contact. For this to happen, you need enough relative velocity(engine speed). The load also can not go above the point at which the file become unstable(throttle).

My theory behind an automotive manufacturer putting such a warning in the owners manual is that your typical car owner (not an enthusiast or someone who is mechanically inclined) will likely assume that if the engine temperature shows that it's warm after idling for a few minutes, the car is good to be driven in a normal manner. I'd like to think that most of us on this site knows that's not true (as has been previously stated, transmission and rear diff fluids are still cold, tires not warm, etc), but a lot of people don't think of it that way.

I imagine that a high gear:low rpm ratio may likely have a slower wear and tear pattern than simply zooming off at high speeds while trying to deal with thick transmission oil. This is likely where the warning comes into play. Yes, they'll both likely cause failure at some point down the road, but the latter may cause issues while the car is still under warranty, while the former wont. Just manufacturers trying to cover their own ass, perhaps?

[hk20000]

letting a car warm up on idle in excess of minutes has the same effect of leaving a car idle for a long period of time.

the oil pressure during this whole time will be less than optimal, causing mechanical wear to valve adjustment components on some engines which require oil pressure to operate.

that's really all there is to it.

[shenmecar]

i think its better not to idle for 5-10 mins...
my instantaneous mileage when idling in the cold is like 2.0l/hr!!! holy shit!

thats your fuel consumption, not mileage.

[stanton]

HAHAHAHAHAHHA try living anywhere else then Vancouver and this thread might have some relevance. Outside the window of my office right now I can see over 45 trucks and car idling so people will not freeze to death on there drive home from work. yey for minus 45degrees with the wind chill. I agree it might not be optimal for a high performance engine, but for the majority of the vehicles it doesn't even effect them. If it is so bad for a engine to warm up by idling why do they all come with remote start as OEM in everything from Lexus, Mercedes, on down to Chevy's?

[sonick]

HAHAHAHAHAHHA try living anywhere else then Vancouver and this thread might have some relevance. Outside the window of my office right now I can see over 45 trucks and car idling so people will not freeze to death on there drive home from work. yey for minus 45degrees with the wind chill. I agree it might not be optimal for a high performance engine, but for the majority of the vehicles it doesn't even effect them. If it is so bad for a engine to warm up by idling why do they all come with remote start as OEM in everything from Lexus, Mercedes, on down to Chevy's?

Point taken, but regardless of temperature, even in spring/summer/fall I know people who still idle their engine to temperature before driving.

[Mugen EvOlutioN]

HAHAHAHAHAHHA try living anywhere else then Vancouver and this thread might have some relevance. Outside the window of my office right now I can see over 45 trucks and car idling so people will not freeze to death on there drive home from work. yey for minus 45degrees with the wind chill. I agree it might not be optimal for a high performance engine, but for the majority of the vehicles it doesn't even effect them. If it is so bad for a engine to warm up by idling why do they all come with remote start as OEM in everything from Lexus, Mercedes, on down to Chevy's?

-45 C ? tats gonna tear up ur entire face just for walking on the street lol


remote start FTW
:thumbsup:

[shenmecar]

-45 C ? tats gonna tear up ur entire face just for walking on the street lol


remote start FTW
:thumbsup:

I think he meant it feels like -45 with the wind, maybe the ambient temperature is -35? :haha:

[Great68]

For my MS3, when it's cold the computer will idle it at ~1500rpm and then slowly drop. I will let it idle until the it drops down to about 1000rpm or until my windows defog.

For the Mustang, well it's carbureted and chokeless. Even in the summer I have to idle it for a good 5-10 minutes before it's remotely driveable.

[benwang]

get a block heater and plug in your car overnight.

[danizer]

thats your fuel consumption, not mileage.

my bad :)

[stanton]

I think he meant it feels like -45 with the wind, maybe the ambient temperature is -35? :haha:


Actually it warmed up today, it hit a high of -27C. Kinda nice out since its a dry cold. lol

[Volvo-brickster]

For the Mustang, well it's carbureted and chokeless. Even in the summer I have to idle it for a good 5-10 minutes before it's remotely driveable.

:haha:

I don't miss my carbureted volvo one bit

winter sucked big time...manual choke all the way out and the thing still wouldn't hold an idle without me pressing on the gas

[fliptuner]

Diesels don't run worth shit when they're cold. They need to be well warmed to run efficiently. They also don't use much fuel when warming up.

When you see a diesel blowing clouds of black smoke it's usually 1 of 3 things:

-not at operating temperature
-tuned for performance = more fuel
-out of tune = dumping fuel

My Mk3 Golf TD gets 2 glowplug cycles, start and high idle for 10 minutes, low idle and drive gently til it's at operating temp. It would run like a bag of shit if I only warmed it up for 2 minutes in the winter.

[TRD Rs200]

why not, I've been warming cars in winter since i got my license

[spoon.ek9]

in light of what's been said in previous posts, it seems that idling a few minutes + light driving until all components warm up is the best combination. unless we get that explanation from your source OP :p

[GabAlmighty]

I've revved a turbo car to redline as it started in negative temperatures... Just remembering the sound that thing made makes me shudder.

[RabidRat]

I've revved a turbo car to redline as it started in negative temperatures... Just remembering the sound that thing made makes me shudder.

LOL GAB WHY?

[GabAlmighty]

LOL GAB WHY?
hahaha, wasn't my car:p I was like 15 and my parents told me to go start and warm up their xc70. I felt really bad after

[CP.AR]

hm... I'm certain my Acura manual said that warming up is not necessary as the engine will automatically upshift (auto tranny) at a higher rev when it is cold. All it said was not to exceed 4.5k rpm when it was cold or something.

I will check and scan the page if I can find it

[orange7]

hm... I'm certain my Acura manual said that warming up is not necessary as the engine will automatically upshift (auto tranny) at a higher rev when it is cold. All it said was not to exceed 4.5k rpm when it was cold or something.

I will check and scan the page if I can find it

really? I don't recall reading that from my Acura manual.

[GabAlmighty]

I don't have a manual. My car's gonna take what I throw at it or its going to the junkyard.

[CP.AR]

really? I don't recall reading that from my Acura manual.

I vaguely remember it, I think it was in the maintainence section or something... maybe I read it from somewhere else, but I'm too lazy/cold to walk to the garage right now and get the manual - maybe tomorrow :D

[Supafly]

I've revved a turbo car to redline as it started in negative temperatures... Just remembering the sound that thing made makes me shudder.

same here..before i swapped motors on my old car..
wanted to show off my turbo setup....the spool noise was scary...sound like its got no bearings..:(

[GabAlmighty]

same here..before i swapped motors on my old car..
wanted to show off my turbo setup....the spool noise was scary...sound like its got no bearings..:(
Hahaha, oh god that's terrible. When I did it the whole motor/car just shook itself violently and made god awful noises. I felt kinda bad for it