Stephen Ciatti, a former drag racer who has a PhD in mechanical engineering from the University of Wisconsin-Madison and now oversees all of the combustion engine work at the Dept. of Energy’s Argonne National Laboratory, explains how idling hurts engines, excerpted below from the article: “Stop hurting your engine by idling the car when it’s cold out” http://www.businessinsider.com/heres-what-idling-your-car-in-the-morning-is-doing-to-your-engine-and-its-not-good-2016-1
Under normal conditions, your car engine runs on a mixture of air and vaporized fuel, gasoline in this case. When that mixture enters a cylinder, a piston compresses it, which — at the risk of oversimplifying — generates a combustion event, powering the engine. But when it’s cold outside, gasoline is less likely to evaporate. Your car compensates for this initially by adding more gasoline to the air-vapor mixture — what Ciatti calls running “rich” — and that’s where the problem begins.
“That’s a problem because you’re actually putting extra fuel into the combustion chamber to make it burn and some of it can get onto the cylinder walls,” Ciatti said. “Gasoline is an outstanding solvent and it can actually wash oil off the walls if you run it in those cold idle conditions for an extended period of time.” Over time, that washing action can “have a detrimental effect on the lubrication and life of things like piston rings and cylinder liners,” which are critical to running the cylinders and pistons that breathe life into your engine, Ciatti said.
The bottom line: Contrary to popular belief, idling your car does not prolong the life of your engine; rather it shortens it.
“Contrary to popular belief, idling your car does not prolong the life of your engine; rather it shortens it.”
Only those who are fairly ignorant regarding automotive technology would believe that idling prolongs the life of the engine.
There are people who actually believe that if you place a knife under your bed, it cuts your pain in half, but those folks are just as misinformed as those who think that extended idling is good for an engine.
I’d say that quote is in response to the viewpoint that it’s better to let the engine idle to warm up in cold weather to allow the oil to circulate in the engine and to not put a load on a cold engine. But the fact is oil will circulate in an engine within 30 seconds unless at or below 0º; it takes a minute or so in extreme cold. Then driving gently to warm up is best. You’re putting no more of a load on a cold engine by driving gently for a minute or two, plus non-engine moving parts such as the transmission, bearings, catalytic converter warm up faster when driving. And of course you’re getting some MPG, not 0.
when it's cold outside, gasoline is less likely to evaporate
Engines burn droplets of fuel created by the fuel injector geometry, not vapor. Cold intake tracts can cause these droplets to puddle until the tracts are warmed. Gasoline blended for winter use is mandated to prevent puddling at lower temperatures.
Your car compensates for this initially by adding more gasoline to the air-vapor mixture — what Ciatti calls running "rich
Modern, fuel injected, cars run rich only at start up and do so whether idling or driving to warm the catalytic convertors and the intake tract up to operating temperature. Once the cat is warm, the engines are commanded to run at stoichemetric (14.7:1 air fuel ratio) whether at idle or driving. Vaporization of fuel no longer is a problem as the intake tract and the cylinder head ports are warm enough prevent puddling of cold fuel.
The article NOT copied here brings things back to reality. This portion of the article is simplistic and incorrect.
I Guess This Explains Why Taxi Cab And OTR Truck Engines Don’t Last Very Long… Oh Wait, That’s Not Right! :neutral:
CSA
Oil doesn’t take 30 seconds or longer to “flow” and a minute below 0 degrees. If that were the case, then engine would rapidly destroy itself in cold weather. Watch your oil pressure gauge, and time it. It just isn’t true.
And;
You're putting no more of a load on a cold engine by driving gently for a minute or two
This is incorrect as well. Any driving loads the engine more than idle.
But we agree that gentle driving warms the engine and cats and the rest up more quickly than idle.
CSA - these vehicle engines last a long time as long as they adhere to severe-duty oil changes and more frequent engine rebuilds. Avoiding excessive idling would put off or negate these expenses.
We.ve had this post many times! All agreed that letting the engine idle just long enough to get the oil circulating to the valve gear is enough. Unless it’s very cold and you need to defrost your windshield first.
When we left carburetors behind extensive idling became unnecessary.
Having said that, taxis and police vehicles idle a lot out of necessity. But the modern fuel measurements keep the fuel/air mixture in the right proportion once the engine is warmed up.
The statement that taxi engines don’t last long is pure baloney. I’ve ridden in countless taxis with over 500,000 miles on them; they just accumulate those miles in a much shorter time by going as much as 100,000 miles a year!!!
Mustangman - oil is thicker the colder the engine is. It does take longer to fully flow throughout the engine and lubricate it properly, the colder it is. As to any driving placing more of a load, not if you don’t exceed the idle rpm which can be around 1,500-2,000 - of course, you can’t do that if you have to get right onto a 40 mph road.
I neither think that letting an engine warm up for 5 minutes will lengthen the engines life, nor do I feel that it shortens the life of that engine to make much of a difference.
If I lose 5% of my engines life (my truck is over 250’000) 12’500 mi. that is a drop in the bucket said the professional mouse milker.
Anyone in the colder states knows that just your exhaled breath can fog your windows in a minute or two if the defrosters are not warming the air a bit.
I know that driving with a window down part way will help, but when it’s 22 degrees out the last thing you want is cold air blowing in the window.
Now my wife; it was 30* this am and she let her van warm up for half an hour. I’m not arguing the point with her…I have to live with her!!! If you want to argue the point, I’ll send her to your house. Beware she carries a knife!!!
As far as this “Stephen Ciatti” is concerned…he looks a little shifty to me anyway.
I’d bet that if we drive to his house the next day that it’s below zero, and park early enough in the morning, we’d see nothing but an arm sticking out the screen door as he presses that “auto Start” button on his key fob. Then he goes back inside to eat his breakfast.
Just kidding…I don’t know the guy.
I just don’t feel that a few minutes…less than 5…is going to have much of an impact. Plus, I do believe that it is harder on the internals of the engine to go from a stone cold engine right onto the highway
Below 30*, I let the engine warm for a minute or two. By the time I get to the freeway ( 4 miles) the heater is ready to blow warm air.
Yosemite
CSA - these vehicle engines last a long time as long as they adhere to severe-duty oil changes and more frequent engine rebuilds. Avoiding excessive idling would put off or negate these expenses.
Adhere to severe-duty oil changes?
I’m already on that schedule.
@Idle-Free
Ever read your vehicle’s Owner’s Manual? Almost every vehicle is subjected to severe use, according to its manufacturer.
Put off or negate more frequent rebuilds?
Let’s not get silly, here!
I drive my vehicles over a quarter million miles with no rebuilds necessary. We idle them when we want to idle them. My wife warms her car by remote-start. My cars rust out before they wear out!
Let me guess… you think as a “secondary” benefit to not idling that we’ll help save the planet.
Is this correct?
CSA
oil is thicker the colder the engine is. It does take longer to fully flow throughout the engine and lubricate it properly
@Idle-Free Of course oil is thicker when colder but it does not take 30 seconds to a minute to circulate.
if you don't exceed the idle rpm which can be around 1,500-2,000 - of course, you can't do that if you have to get right onto a 40 mph road
Read your idle on the tach, it is about 600 to 800 rpm, not 1500 to 2000. Remove your foot from the brake. Just how fast are you going? 1-2 mph? 2000 Rpm for a couple of my cars is 50 mph. Rpm is not load, it is the engine’s speed. Load is not speed.
CSA - Actually, I’ve read many owner’s manuals. Some of them point out that if you idle for an extended period, you will be subject to more frequent oil changes. My 2014 Subaru Impreza’s manual (and all late model Subaru manuals) states, “Avoid unnecessary engine idling”. And here’s a quote from the 2015-2016 Ford F-Series Power Stroke diesel pick ups: “Note: Idling in cold weather does not heat the engine to its normal operating temperature. Long periods of idling, especially in cold weather, can cause a buildup of deposits which can cause engine damage.” Straight from the horse’s mouth.
As to your guess, you’re almost correct. I believe in the multi-benefits in avoiding unnecessary idling: conserving energy, lessening carbon emissions, improving air quality, and saving money.
And I will respect the advice of Stephen Ciatti, who is an expert.
“Almost every vehicle is subjected to severe use, according to its manufacturer”
I agree with that, with an “exact” reading of the schedule. but the question is: How seriously do we take this? If the manufacturer took it seriously, it would negate any possibility of warrantee repairs. For example, I change my oil every 5k miles. Spec is 6k, severe use 3.7k (see below). So I would not be eligible for any engine warrantee work.
(one line says 3.7k, another says 3k. huh?)
“Extended idling in cold weather is bad for engines”
Your Definition Of “Cold Weather” Must Be Somewhat Different Than Mine.
I live north of the 45th parallel. Warm-up is essential to safe driving!
It has not warmed to freezing here, as I write.
Do you know what’s worse than a perceived engine wear savings?
Car damage and injuries caused by not warming the vehicle properly in “cold weather.”
Poor visibility caused by ice and frost on the windows and a defroster that does nothing to keep windows clear right after they are scraped clean and you get under way.
A wife that desires and deserves to leave for work without her teeth chattering. A freezing driver is not a safe driver.
Safety or (imagined) engine wear? I’ll take safety, thank you!
Heat in a car is not just a comfort item for many of us. It’s a necessary safety item.
How do I know? I’ve been driving in “cold weather” for over 5 decades.
Even if it shortened my engine life by half, I’d still warm up prior to driving, most of the time.
CSA
As for frost on windows when cold. Haven’t had that problem since we bought a house with a garage. Even when -10…no frost on windows.
Warm person when driving…many vehicles now have seat warmers. Wife has them in her Lexus. They work real well in getting the person warm long before the heater is putting out warm air.
I start my truck…then immediately start to drive. I take it slow and easy when real cold til I get to the highway (about 5 miles away). By the time I get there…the heat is blowing out hot air…and cabin is starting to warm. I can attest that there has not been any undo engine damage doing it this way…since we’ve had several vehicles with well over 300k miles with no internal problems what-so-ever.
@Idle-Free
I think it’s terrific if you never idle your engine!
I also, feel that if you or anybody else decides that taking frequent showers or frequently washing socks and underwear wastes energy and water resources… that’s terrific, too! Go for it, but not within olfactory range, please.
I work on my own vehicles, seven of them are cars. I do maintenance and repairs. I have been doing this and driving for fifty+ years.
What I don’t need is somebody with an agenda telling me how I should be driving and operating my vehicles.
CSA
CSA - You are fully correct about the safety issue. I always make a point (except right here unfortunately I initially didn’t) that adequate defrosting is essential. You can warm up stationary for 30 seconds and be ready to continue warming up by driving gently, but if you can’t see out of an undefrosted windshield, you will have to idle until it’s clear. This doesn’t occur too often however, as defrosters are pretty powerful, but it can be an issue, especially driving into a rising sun.
I live in Vermont, so it’s cold here in the winter. I’m well into my 60s and bundle up and I’m a bit uncomfortable for a minute or so, but it never affects my ability to drive. However, I wouldn’t expect a frail elderly person or infant to be in a car without a few minutes of warming up.
One other thing that should be made clear: 30 seconds of initial warm up only applies to light-duty vehicles. Heavy-duty diesels need 3-5 minutes to warm up no matter the temperature range, unless a block heater is used.
“Let me guess… you think as a “secondary” benefit to not idling that we’ll help save the planet.”
"Is this correct?"
CSA
“As to your guess, you’re almost correct. I believe in the multi-benefits in avoiding unnecessary idling: conserving energy, lessening carbon emissions, improving air quality, and saving money.”
I can spot them a mile away.
“And I will respect the advice of Stephen Ciatti, who is an expert.”
“Expert,” not to mention he’s paid by the DOE to reinforce their social agenda!
The last one of these “experts” that I listened to (my kids bought me the book as a joke) said that parts of the U.S. would now be under water because of wasteful ways. Turns out… get this… that the reason we aren’t is because the continents are much more absorbent than the “experts” realized. Right.
@Idle-Free
This seems important to you. Let me ask another question… Do you think that Bernie Sanders would be my best choice for the presidential contest? Who would you recommend?
CSA