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Warming up your car before driving in cold weather can damage the engine (2016)

businessinsider.com

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Re: Warming up your car before driving in cold weather can damage the engine (2016)

#121

Post by nomel »

pvaldes wrote: post #64

If your oil is too thick to spread accurately, the problem is that you are using an incorrect oil, not that your motor is cold. Oil --must-- work even when is cold. If your area reaches -40F in winter you will need a "0 Winter 30" oil grade; or 0W/30, that is more expensive but very thin so it will not freeze 5W/30 will work until -31F 10W/40 will not freeze until 0F. This is the standard grade used for both winter a…

> Oil --must-- work even when is cold.

“Must work when cold” is not the same as “must work at load when cold”. Most modern cars have a limited redline, until the engine warms, because of this.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#122

Post by danw1979 »

kube-system wrote: post #113
brookside wrote: post #109

Earlier quoted context omitted.

Are you aware not using the heater does not affect fuel efficiency in an ICE car? Heaters in ICE cars take the pull existing heat from the engine. (I'm not aware of how your hybrid is programmed, it may or may not turn the engine on sooner if the heat is on.) Letting off the gas 100 meters before a stop light and coast that will save gas, but of course it won't be more efficient to brake for the 100 meters before a s…

> Are you aware not using the heater does not affect fuel efficiency in an ICE car? Heaters in ICE cars take the pull existing heat from the engine. It does in many hybrids, particularly those that can operate in EV mode at higher speeds. When heat is commanded, they often will idle under even under no load conditions just to maintain coolant temp. These are conditions which otherwise would use zero fuel. A fun party…

Seconded by a plug-in Prius owner.

Sadly the climate control pre-conditioning on the PiP only uses the battery (or mains, if left plugged in) to cool the interior before you set off, not to heat it. I guess this is because it doesn’t have reverse cycle AC, so can’t pump heat into the interior, only out of it. Far less useful in the UK than California.

So if you want heat, you have to run the engine.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#123

Post by walnutclosefarm »

I don't doubt that the expert consulted for this article knows way more about gasoline engines than I do, but the article itself contains some flat-out falsehoods. In particular the line "But don't confuse warm air coming from your car's radiator with a warm engine." is just wrong. The engine temperature sensor actually senses the engine coolant temperature, and if your dash is blowing warm air, then the coolant is way warmer than 40F,and the engine has leaned the fuel mixture.

I also wish the expert had addressed the real question in this warming scenario - which is how many piston cycles (crankshaft revolutions) you run with an over-rich fuel mixture. It's certainly true that engine warm-up takes longer at low rpms, but it also true that if you run at driving rpms, while the elapsed time to end the over-rich fuel will be less, you will have cycled the pistons many times more than at an idle. It's the piston movement he's tagging as the engine wear culprit, and it's not at all clear how many more piston cycles there really are, if you warm at an idle. It's not even clear there are more, thinking from first principles.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#124

Post by mikrotikker »

jimmaswell wrote: post #91
Brian_K_White wrote: post #47

I'm sure the cited expert really is an expert, but this article fails miserably at conveying any cohesive understanding from them to you. It's full of conclusions that don't follow from their leading statements. My understanding about warming up an engine before putting load on it had nothing to do with fuel or power steering fluid, it was about thermal expansion of all the machined parts that suffer wear if they are…

Anecdotally, my transmission doesn't shift as well if I drive it right away in the cold.

Yea on cold mornings I have to skip 2nd gear and go straight to 3rd, since I can't get into 2nd gear the first few times.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#125

Post by Gibbon1 »

nickff wrote: post #62
Brian_K_White wrote: post #47

I'm sure the cited expert really is an expert, but this article fails miserably at conveying any cohesive understanding from them to you. It's full of conclusions that don't follow from their leading statements. My understanding about warming up an engine before putting load on it had nothing to do with fuel or power steering fluid, it was about thermal expansion of all the machined parts that suffer wear if they are…

I work on the repairs side of this industry (diagnostic tools), and have come to the conclusion that while the thermal expansion is an issue, it’s probably not the largest or most fundamental one. When an engine idles (with no load), it produces relatively little heat. Comparatively, an engine running faster, under load produces much more heat. The engine will warm up more quickly and less evenly when loaded, likely…

> On the other hand, modern lubricants are very good at handling different temperatures.

I think this is the key difference between now and what used to be.

Also suspect modern engines are more carefully designed to handle thermal expansion.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#126

Post by WalterBright »

Glawen wrote: post #90
WalterBright wrote: post #75

The best thing you can do to make your engine last is change the oil regularly.

Engine oil gets a lot of cargo cult on automotive forums. Personally, I never saw an engine die because it missed the schedule by some thousands km. I wait until my car tells me it needs an oil change, and then I wait a bit more :).

I've never had an engine wear out on me and start burning oil.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#127

Post by pdonis »

lazide wrote: post #86
pdonis wrote: post #49

Earlier quoted context omitted.

> I don't see how idling would 'strip it away.' What the article is saying here is technically correct, but I doubt the effect is as large or as detrimental as the article says. The key point is that, as the piston moves up and down in the cylinder, the part of the cylinder wall that is traversed is alternately wetted by oil and gasoline. When it is wetted by gasoline (i.e., when the piston is at the bottom of its st…

If you are getting more than a super tiny film of oil in the cylinder, you’re burning oil because your rings are toast. That has nothing to do with temperature, usually.

> If you are getting more than a super tiny film of oil in the cylinder, you’re burning oil because your rings are toast.

The "cylinder" is more than just the portion where combustion occurs, when the piston is at or near top dead center. The portion the article is talking about is the portion that, as I said in my previous post, is exposed to gasoline when the piston is at the bottom of its stroke--as it will be at the end of both the intake and the power strokes in a 4-stroke engine. If the mixture is rich, there will be extra gasoline present under those conditions that, according to the article, could dissolve the oil wetting the cylinder walls. That will be the case even if the rings are fine. I just don't think it's anywhere near as significant as the article claims, because, as the poster I responded to pointed out, even if some oil is dissolved in the extra gasoline, it will be replaced as the piston rises again and that portion of the cylinder wall is on the oil side of the rings.

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#128

Post by lazide »

pdonis wrote: post #127
lazide wrote: post #86

Earlier quoted context omitted.

If you are getting more than a super tiny film of oil in the cylinder, you’re burning oil because your rings are toast. That has nothing to do with temperature, usually.

> If you are getting more than a super tiny film of oil in the cylinder, you’re burning oil because your rings are toast. The "cylinder" is more than just the portion where combustion occurs, when the piston is at or near top dead center. The portion the article is talking about is the portion that, as I said in my previous post, is exposed to gasoline when the piston is at the bottom of its stroke--as it will be at…

The cylinder has rings to remove that oil, hence my comment.

There should also be very little to no gasoline contacting the cylinder walls at the bottom of the stroke, or at all. The air currents inside rarely directly contact the cylinder walls.

If you have any evidence that the effect you’re describing exists, it would be nice if you link to it!

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#129

Post by winrid »

willis936 wrote: post #74
bombcar wrote: post #71

Earlier quoted context omitted.

Some vehicles have oil heaters to get the oil to operating temperature before even cranking. These engines are often large enough to park a car inside, however.

My 2018 car (gasoline, turbocharged, direct injection) has coolant and oil temp readouts. The increase in coolant temp from a cold start leads the oil temp by a few minutes (exact time is dependent on ambient temperature and load profile). Once the oil temp starts to get above 150F it very quickly gets to the operating temp (220F), so I view that as the point that it's okay to go above 3000 RPM. If there are oil heat…

Street cars have been using coolant/oil heat exchangers to bring oil up to temp faster and regulate its temperature under load since at least 1999 (source: VW's 1.8T, AEB and AWP motors).

https://store.ngpracing.com/acm-oil-cooler-heat-exchanger-1-...

Re: Warming up your car before driving in cold weather can damage the engine (2016)

#130

Post by aetherspawn »

There is no oil where they claim it in the cylinder on Japanese engines, otherwise they would be burning oil (and they don't). At least not for the first 300,000kms or so. If the fuel can ever burn the oil, that's a really bad thing.

Also the article claim about the power steering pump is completely wrong, as the pump runs no matter the speed or load of the pump; it will just pressure-relief through the pumps internal relief valve.

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