Warming vehicle up in cold temps harms engine.

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Interesting read..

In the thick of winter, the common wisdom is that when you are gearing up to take your truck out in the cold and snow, you should step outside, start up your engine, and let it idle to warm up. But contrary to popular belief, this does not prolong the life of your engine; in fact, it decreases it by stripping oil away from the engine`s cylinders and pistons.

In a nutshell, an internal combustion engine works by using pistons to compress a mixture of air and vaporized fuel within a cylinder. The compressed mixture is then ignited to create a combustion event-a little controlled explosion that powers the engine.

When your engine is cold, the gasoline is less likely to evaporate and create the correct ratio of air and vaporized fuel for combustion. Engines with electronic fuel injection have sensors that compensate for the cold by pumping more gasoline into the mixture. The engine continues to run rich in this way until it heats up to about 40 degrees Fahrenheit.

"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," Stephen Ciatti, a mechanical engineer who specializes in combustion engines at the Argonne National Laboratory, told Business Insider. "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."

The life of components like piston rings and cylinder liners can be significantly reduced by gasoline washing away the lubricating oil, not to mention the extra fuel that is used while the engine runs rich. Driving your car is the fastest way to warm the engine up to 40 degrees so it switches back to a normal fuel to air ratio. Even though warm air generated by the radiator will flow into the cabin after a few minutes, idling does surprisingly little to warm the actual engine. The best thing to do is start the car, take a minute to knock the ice off your windows, and get going.

Of course, hopping into your car and gunning it straightaway will put unnecessary strain on your engine. It takes 5 to 15 minutes for your engine to warm up, so take it nice and easy for the first part of your drive.

Warming up your car before driving is a leftover practice from a time when carbureted engines dominated the roads. Carburetors mix gasoline and air to make vaporized fuel to run an engine, but they don`t have sensors that tweak the amount of gasoline when it`s cold out. As a result, you have to let older cars warm up before driving or they will stall out. But it`s been about 30 years since carbureted engines were common in cars.

So unless you`re rolling in a 1970s Chevelle-which we assume isn`t your daily driver-bundle up, get into that cold car, and get it moving.
 
TO sum up the important part(s) .. the ONLY time I let mine idle for an *extended* period is when the windows are fogged or iced over and won`t quickly clear.

The best thing to do is start the car, take a minute to knock the ice off your windows, and get going.

Of course, hopping into your car and gunning it straightaway will put unnecessary strain on your engine. It takes 5 to 15 minutes for your engine to warm up, so take it nice and easy for the first part of your drive.
 
I start my car to warm the inside cause i dont like driving in a super cold car, and now that i have a baby i dont want him to be super cold either. Maybe i`ll have to move to florida or texas
 
I lease my car. As long as everything last 36 month me no care. I let car run one minute for every 10 degrees below freezing. Over 32 f. Start and drive. Trick is using the correct weight oil for the temperature.
 
I lease my car. As long as everything last 36 month me no care. I let car run one minute for every 10 degrees below freezing. Over 32 f. Start and drive. Trick is using the correct weight oil for the temperature.

If your car takes 30 weight
Go with 0w30 for winter
Of it takes 20weight

.use 0w 20 in winter
 
I wonder if such practices actually have a real/functional effect...whether it really matters. Cop cars idle for innumerable hours, and when they`re deemed "worn out" some Cab Co. buys them and they suffer further abuse for a few hundred thousand more miles.

I lease my car. As long as everything last 36 month me no care..

While it might be a form of Autopian Heresy, that whole "just lease something and don`t worry about it" can make a lot of sense IMO. I used to knee-jerk-criticize leasing as a silly waste of money, but *just not having to think about it* has some value too.
 
For my truck and grand prix I will let them run for 5 min or so.

My GTO is another story. Due to the extensive engine modifications and fuel system modifications along with being tuned on a Speed Density operating system vs a MAF sensor I have to let it get up to close to operating temp. If not then it will not have enough heat in it to burn off the excess fuel on cold starts and will sputter down the road until warmed up.

Kinda the same reason if you hear drag guys say I need to warm it up and get some heat in the engine.
 
Another "expert" that prolly never turned a wrench...Lolz... I`m sure everything in that article could be true, but when was the last time anyone heard of properly maintained modern engine failing due to worn piston rings or cylinder walls???

What internally is more likely to go bad in a modern engine is bearings and / or valve train components. Timing chain guides also frequently go bad - but that is semi-irrelevant here.

I still say it is better to let an ice cold winter engine idle for at least minute or so before taking off. This lets the contracted metal parts expand from a bit of warmth and get closer to their running tolerances before they are under any load. It also lets the oil flow better to do its thing.

The author is also negating a car idling vrs under load warms up a bit faster in the winter due to ice cold air not being blown through the radiator at idle.

But then again, I was just a dumb mechanic - so believe what you will.


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I do not think it makes any practical difference on the life of the engine to idle. It is not like you hear "My engine failed since I let it idle too much". Modern cars are computerized and take care of themselves. When the dealer wanted to debug an AC issue on my car, they let it idle in the shop for a very long time in order to finally capture the issue. Many lease anyway and would never know the ill effects.
 
The Jetta and Camry stay in the garage, so typically I let them idle down and take off. The truck, you have to idle it for a while. The top end of the motor is worn slap out and will knock so bad until it gets decent oil pressure. It typically sees lots of idle time as well.

Police spec Crown Vics idle while in service a ridiculous amount of time, then get sold to Taxi fleets that do the same thing. Most go well over 600K before being retired.
 
From my owners manual...

"Allow the engine to idle for at least 30 seconds after starting. Do not race the engine while warming it up. Drive at moderate speed for a short distance first, especially in cold weather.

Tell your wife or girlfriend to get in a cold vehicle. LOL. As a general rule I follow the above.

Some states have idiling laws? New to me.

Idling Laws By State | CDLLife
 
Another "expert" that prolly never turned a wrench...Lolz... I`m sure everything in that article could be true, but when was the last time anyone heard of properly maintained modern engine failing due to worn piston rings or cylinder walls???

What internally is more likely to go bad in a modern engine is bearings and / or valve train components. Timing chain guides also frequently go bad - but that is semi-irrelevant here.

I still say it is better to let an ice cold winter engine idle for at least minute or so before taking off. This lets the contracted metal parts expand from a bit of warmth and get closer to their running tolerances before they are under any load. It also lets the oil flow better to do its thing.

The author is also negating a car idling vs under load warms up a bit faster in the winter due to ice cold air not being blown through the radiator at idle.

But then again, I was just a dumb mechanic - so believe what you will.


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As another ASE-Certified dummy, I wholeheartedly agree. No way am I going to put my engine under load before the oil has had a chance to circulate and warm up a bit. I`ve seen far, far more engine failures due to bad main/rod bearings than piston rings and cold weather brings out the worst.

Bill
 
Police spec Crown Vics idle while in service a ridiculous amount of time, then get sold to Taxi fleets that do the same thing. Most go well over 600K before being retired.

Exactly. And most people would never *believe* the length of perfectly-OK Oil Change Intervals for those 4.6L engines either.
 
What about transmissions?

Another "expert" that prolly never turned a wrench...Lolz... I`m sure everything in that article could be true, but when was the last time anyone heard of properly maintained modern engine failing due to worn piston rings or cylinder walls???

What internally is more likely to go bad in a modern engine is bearings and / or valve train components. Timing chain guides also frequently go bad - but that is semi-irrelevant here.

I still say it is better to let an ice cold winter engine idle for at least minute or so before taking off. This lets the contracted metal parts expand from a bit of warmth and get closer to their running tolerances before they are under any load. It also lets the oil flow better to do its thing.

The author is also negating a car idling vrs under load warms up a bit faster in the winter due to ice cold air not being blown through the radiator at idle.

But then again, I was just a dumb mechanic - so believe what you will.


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I agree.

Fluid needs to circulate through the chambers.

FYI, if you cold start a rotary, drive it quick without warming up and shut it off. You`ll flood it every time, not to mention destroy the seals.
 
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