Thin vs. thick: cold-engine protection

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May 17, 2021
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I don't think over-babying an engine though or lugging it is ideal either. Getting the engine warm as fast as possible within reason is how I look at it.

Probably true. A heavier foot will let the engine get up to temp quicker. No idea if there does exist serious research on which way driving a cold engine lets to less wear.

Major issue isn't oil temp though and I do actually mean the temperature of the oil itself, not the oil temp as an indicator of the engine temp. Biggest issue is the very initial moment of engine start itself, since this happens with zero oil pressure, causing a short phase of mixed friction. This is the reason why huge diesel engines in ships and locomotives use to have both a (fuel driven) pre heater and an independent (electrical) oil pump, that starts before the engine is opereating. Start button is unblocked not before a certain oil pressure is reached. Second main issue is due to expansion, as the pistons will heat up way quicker than the engine block will.

Agree, another unneccessary topic, but I couldn't resist.....
 
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In my opinion engine wear when cold is overblown. If you are sensible and allow time for the oil pressure to build up before taking off then you should have no worries. For those who start up on a cold morning and put it into gear and take off, you should think about how you are treating your vehicle. The oil will do its job regardless of the viscosity.
 
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I don't think over-babying an engine though or lugging it is ideal either. Getting the engine warm as fast as possible within reason is how I look at it.
I agree. I also think an engine cruising on the highway, that got up to speed w/o mashing the gas pedal is going to warm up faster than an engine idling at traffic lights, taking off and then stopping for every light while warming up. Lets not forget taking off from stops is harder on an engine than cruising at highway speeds. IMO the person who drives a few minutes to the highway and cruises is doing his engine a favor. The guy going from one light to the next and stopping isn't doing the engine any favors during warm up. Regarding viscosity unless it's way below zero a 5W30 is reaching the engine parts and lubing them as fast as a 0W20 is.
 
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IMHO, there are things in life worth worrying about and things that are not... I put this in the not category. I’m running 0w16 in our Toyota and not missing any sleep over it.
 
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I spend most of my time in an area where annual temps run from -20 to +90. I've always been able to drive for a bit on low speed surface streets a bit before needing to load the engine much. In winter, block heaters make the engine think that it's warm summer day. I use 5-30 and 10-30 synthetics and have had no engine related issues even as I run my vehicles for years and most for plenty of miles.
Were are talking Paramount California cold Starts.
 
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I can see engines designed for light work/load or low revving engines such as hybrids or light city or commute cars using thinner oils which also improves the fuel economy ... However, regarding cold starts and as long as you meet the W spec, wouldn't thicker oil according to physics , heat up or warm the engine up faster than thinner oil? I'm sure I read that somewhere.

Viscosity grade selection for those who ignore the owner's manual (i.e. most bitog members) is as follow:

old-timers solution:
not too thin and not too thick. Thin enough to meet your winter spec and thick enough to meet your load ... or something to that effect.

new-timer's solutuon:
Euro 0W-40 baby. It should cover all your needs. :)

But back to my question, wouldn't thicker oil warm-up quicker? Gain a few minutes or seconds or even milliseconds? lol
 
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But back to my question, wouldn't thicker oil warm-up quicker? Gain a few minutes or seconds or even milliseconds?


I doubt it. What would be the benefit of a few seconds anyway? Besides, too many variables.
 
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But back to my question, wouldn't thicker oil warm-up quicker? Gain a few minutes or seconds or even milliseconds? lol
Theoretically yes, if all other factors were held constant. The shearing drag forces on thicker oil is higher which makes it heat up more as it goes through the journal bearings, etc. But I doubt if the delta time for the different weight oils to get to the same temperature is going to make any tangible difference.
 
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What helps a lot on modern cars is their use of a coolant-to-oil heat exchanger. It's function is two-fold: It helps warm the oil up faster during engine warm-up, and also helps cool the oil when the oil is at full operating temperature, as long as the radiator works well and keeps the coolant temperature under proper control.
 
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Am I the only one here who dreads the most engine wear when the engine is cold? I am especially paranoid about getting on the freeway with a cold engine. Cold engine seems to be an afterthought for most people here when choosing the oil viscosity. I am at no such ease.

I understand that if you are driving really fast and hard, a thicker oil could benefit you. However, for the rest of us, why not worry about the cold engine instead, where the worst wear supposedly happens? I feel a lot safer with the thinnest oil that works when my engine is cold. You can see from my signature line that my factory fill is 0W-16, and I am proud of that. Prius Prime is a car that literally gets over 100 mpg end-to-end on gasoline only in crawling freeway traffic, which beats motorcycles in fuel economy. It is obviously not meant for being driven fast, and 0W-16 perfectly suits it. I was very careful in breaking in the internal-combustion engine, and I am confident that 0W-16 is keeping it as good as just broken in thanks to its better cold-engine protection.

Your thoughts.

My Alaskan GM gas trucks and SUV's typically last 250K to 300K miles before I sell them. By then, everything is failing around good typically good engines and 4WD or AWD drive-trains.

BTW, my trucks are NOT garaged and are sometimes (seldom) plugged in. I live 55 miles north of Anchorage where overnight temps dip to -30 degs F and stay continuously below zero for typical two-week stretches during our winters.

What's my secret? There isn't one. Outside of running 5W-30 or 0W-40 synthetic oil and other synth fluids, they just start, go, and last. My OCI's are typically 3K to 5K miles and are not out of the ordinary. The other fluids follow a slightly shorter OCI, perhaps shorter than "severe." Oh, I don't warm them up for more than 5 mins, if that, before conservatively driving down our snowy roads.

Drive them and don't worry too much, Gokhan. :)
 
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Joined
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Since you brought up Magnatec :sneaky:... check out the new SP version's CCS @ -30C for its 5W-30 oil: 4000 !
It's dropped considerably as compared to the previous SN/SN+ offering.
Since I live its pricing, I'm going to try it, once again, this coming winter.
Typo. Since I "like" its pricing... not live.
 
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Am I the only one here who dreads the most engine wear when the engine is cold? I am especially paranoid about getting on the freeway with a cold engine. Cold engine seems to be an afterthought for most people here when choosing the oil viscosity. I am at no such ease.

I understand that if you are driving really fast and hard, a thicker oil could benefit you. However, for the rest of us, why not worry about the cold engine instead, where the worst wear supposedly happens? I feel a lot safer with the thinnest oil that works when my engine is cold. You can see from my signature line that my factory fill is 0W-16, and I am proud of that. Prius Prime is a car that literally gets over 100 mpg end-to-end on gasoline only in crawling freeway traffic, which beats motorcycles in fuel economy. It is obviously not meant for being driven fast, and 0W-16 perfectly suits it. I was very careful in breaking in the internal-combustion engine, and I am confident that 0W-16 is keeping it as good as just broken in thanks to its better cold-engine protection.

Your thoughts.
With modern transmissions cars nowadays rev low at high speeds.
 
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Am I the only one here who dreads the most engine wear when the engine is cold? I am especially paranoid about getting on the freeway with a cold engine. Cold engine seems to be an afterthought for most people here when choosing the oil viscosity. I am at no such ease.

I understand that if you are driving really fast and hard, a thicker oil could benefit you. However, for the rest of us, why not worry about the cold engine instead, where the worst wear supposedly happens? I feel a lot safer with the thinnest oil that works when my engine is cold. You can see from my signature line that my factory fill is 0W-16, and I am proud of that. Prius Prime is a car that literally gets over 100 mpg end-to-end on gasoline only in crawling freeway traffic, which beats motorcycles in fuel economy. It is obviously not meant for being driven fast, and 0W-16 perfectly suits it. I was very careful in breaking in the internal-combustion engine, and I am confident that 0W-16 is keeping it as good as just broken in thanks to its better cold-engine protection.

Your thoughts.
My engine runs at full operating temperature for 8-10 hours over 200-300 miles. About 3 of those miles and 5 minutes (10 in the dead of winter) is warmup, so not really. If I did a lot of short trips I would probably go 0w-20 in the winter, but I don't, my foot is made of lead, and I am often hitting 6500rpm so 5w-30 or thicker it is. A hybrid vehicle is a totally different beast and I'd probably just stick with whatever the oil cap recommends.
 
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If your oil started at 8Cst, per university 101, your wear would be incredibly higher.

In the early cold stages, it's thick, providing ample oil film thickness. When it's hot, the additives are there...it's the "warmup phase" that the wear occurs, queue Magnatec...

 
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