Factors that can affect warming up time

[OilUzer]

Originally Posted by OVERKILL
Originally Posted by OilUzer
Originally Posted by PimTac
So a 5w is thicker than a 0w? I'm having difficulty grasping this.


5W will have higher viscosity (cSt) relative to a 0W at cold(er) temperatures ... Since we are talking about cold start/operation and before the oil has reached nominal operating temperatures.


Not always, it depends on what temperature you are looking at. M1 0w-40 is heavier than any GF-5 5w-30 at all temperatures much above where the W-rating is tested, at temperature at which very few people here will be starting their vehicle.


I assume it depends on the oil family or a specific temperature or maybe x40 vs. x30 or the base oil can play a role ... Maybe it can't be generalized to include all oils and all "cold" temperatures ... however i recently compared the viscosity of several xW30 (x=0,5,10) in the same oil family and near freezing and the 10W's had higher viscosity that the 5W's and the 5W's had higher viscosity than the 0W's.

 

[OVERKILL]

Originally Posted by OilUzer
Originally Posted by OVERKILL
Originally Posted by OilUzer
Originally Posted by PimTac
So a 5w is thicker than a 0w? I'm having difficulty grasping this.


5W will have higher viscosity (cSt) relative to a 0W at cold(er) temperatures ... Since we are talking about cold start/operation and before the oil has reached nominal operating temperatures.


Not always, it depends on what temperature you are looking at. M1 0w-40 is heavier than any GF-5 5w-30 at all temperatures much above where the W-rating is tested, at temperature at which very few people here will be starting their vehicle.


I assume it depends on the oil family or a specific temperature or maybe x40 vs. x30 or the base oil can play a role ... Maybe it can't be generalized to include all oils and all "cold" temperatures ... however i recently compared the viscosity of several xW30 (x=0,5,10) in the same oil family and near freezing and the 10W's had higher viscosity that the 5W's and the 5W's had higher viscosity than the 0W's.


Yes, it will depend on how the products are blended, but 0C isn't all that "cold" for any of those oils either, all will be quite fluid.

If we look at the Mobil 1 product family:

M1 AFE 0w-30:
100C visc: 10.9cP
40C: visc: 62.9cP
VI: 166

M1 ESP 0w-30:
100C visc: 12.0cP
40C visc: 63.0cP

M1 5w-30:
100C visc: 11.0cP
40C visc: 61.7cP
VI: 172

M1 EP 5w-30:
100C visc: 10.6cP
40C visc: 59.8cP
VI: 169

M1 10w-30:
100C visc: 10.1cP
40C visc: 63.2cP
VI: 146

Just using the calculated values:

The AFE 0w-30 is heavier than M1 5w-30 at 0C, whilst the ESP 0w-30 is thinner than everything (highest VI of the group).

 

[OilUzer]

Originally Posted by OVERKILL
Originally Posted by OilUzer
One can argue that as a result of thicker oil warning up faster, it will also reduce engine wear since most wear happens during cold starts/operation. maybe the wear reduction is not that significant ... However I think that's one reason it's recommended to run the thickest oil that meets your W rating.


The reduction in wear as the engine warms is due to parts reaching the size they are supposed to be and the activation of heat-activated additives, not the viscosity. Thicker oil will initially shear more, thus creating more heat, but this thins it, so eventually it reaches a point where it is at the same shear rate as whatever you are comparing it to.

One of the reasons thinner oils are being chased by OEM's is that shearing that thicker oil causes more fuel to be burned, which impacts CAFE. Thus, if you can reduce fuel consumption during the warm-up cycle, you increase fuel mileage.

Not sure where the "recommend run the thickest oil that meets your W rating" is coming from? Are you perhaps thinking about VII dosing? In general, oils with a narrower visc spread have historically had a lower dose of VII, but that doesn't factor in base oil selection. You can make a pretty cheap Group II+ 5w-30 that will have more VII than a PAO-based 0w-40 for example, so its not exactly universal.


Regarding "cheap" oil, that's why I said earlier:
"Yes, assuming you don't compromise the oil quality. lol".

I general and not bringing in the oil quality into the equation, the less the spread (xWy) meaning highest x that meets your W rating, the less plastic (vii/vm) in your oil.
If I'm not mistaken, there are some 10W30's out there with no vm. If 10W meets your cold temp rating, why use 0W? and your engine may/will warm-up faster ... But I'm bringing up the oil quality myself

 

[PimTac]

In the end the oil has very little impact on engine warm up.

 

[OVERKILL]

Originally Posted by OilUzer


I general and not bringing in the oil quality into the equation, the less the spread (xWy) meaning highest x that meets your W rating, the less plastic (vii/vm) in your oil.
If I'm not mistaken, there are some 10W30's out there with no vm. If 10W meets your cold temp rating, why use 0W? and your engine may/will warm-up faster ... But I'm bringing up the oil quality myself

[



Yes, AMSOIL makes one. Typically though, manufacturers just appear to use cheaper bases for the narrower spreads. M1 EP 0w-20 for example is basically entirely PAO based, the 5w-20 isn't, because it isn't needed. So both probably have similar levels of VII treat, heck, the 0w-20 could actually be lower

 

[ZeeOSix]

Originally Posted by Mad_Hatter
I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?


If all factors were held constant in the same exact engine, then running thicker oil would cause the oil to warm-up slightly faster due to more heat generated by the shearing friction. There would have to be a big spread in oil viscosity to see a difference viscosity makes on the oil temp gauge.

Patman's example shows that engine RPM has more impact on oil warm-up time than oil viscosity does.

 

[Srt20]

Originally Posted by billt460
Originally Posted by Srt20
Does the MB have exhaust manifold cooling? My guess is it does. Thats why your coolant warms up much faster vs the other. My 2.0T has coolant running through the exhaust manifold and it warms faster than any vehicle Ive ever owned or even driven.

Do you know if any non turbo engines have exhaust manifold cooling? Neither my Jeep or Toyota have turbos, and as I mentioned in my above post, they both produce heat unbelievably quickly from a dead cold start. (5.7 HEMI V-8 & 2.5 4-Cylinder).


I really dont know. I am guessing probably not.

 

[aquariuscsm]

I'd think thin oils would warm up faster due to the nature of the density of the fluid,triggering the temp sensor at a faster rate. Thinking thicker oils could hold in the heat better? I may be completely wrong on this!

 

[ZeeOSix]

Originally Posted by aquariuscsm
I'd think thin oils would warm up faster due to the nature of the density of the fluid,triggering the temp sensor at a faster rate. Thinking thicker oils could hold in the heat better? I may be completely wrong on this!


Thicker oil has more shearing, which produces more heat. If there was no shearing heat at all produced, the oil temperature inside and flowing out of a journal bearing would never increase due to shearing.

 

[Mad_Hatter]

Originally Posted by ZeeOSix
Originally Posted by Mad_Hatter
I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?


If all factors were held constant in the same exact engine, then running thicker oil would cause the oil to warm-up slightly faster due to more heat generated by the shearing friction. There would have to be a big spread in oil viscosity to see a difference viscosity makes on the oil temp gauge.

Patman's example shows that engine RPM has more impact on oil warm-up time than oil viscosity does.

Agreed.. what I wasn't subscribing to was the notion that running a viscosity thick enough to elicit higher bearing temps, was going to impact engine temps in any meaningful way. Ambient temp, fuel/air mixture, rpms...are all going to have a more profound effect than a thicker oil in the crankcase. Heck, running straight coolant/no water (not something I'd do) would probably do more for accelerating the engine warm up process than a change in viscosity.

 

[ZeeOSix]

Originally Posted by Mad_Hatter
Originally Posted by ZeeOSix
Originally Posted by Mad_Hatter
I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?

If all factors were held constant in the same exact engine, then running thicker oil would cause the oil to warm-up slightly faster due to more heat generated by the shearing friction. There would have to be a big spread in oil viscosity to see a difference viscosity makes on the oil temp gauge.

Patman's example shows that engine RPM has more impact on oil warm-up time than oil viscosity does.

Agreed.. what I wasn't subscribing to was the notion that running a viscosity thick enough to elicit higher bearing temps, was going to impact engine temps in any meaningful way. Ambient temp, fuel/air mixture, rpms...are all going to have a more profound effect than a thicker oil in the crankcase. Heck, running straight coolant/no water (not something I'd do) would probably do more for accelerating the engine warm up process than a change in viscosity.


Yep ... keep in mind there's a huge difference between how coolant warms up vs how oil warms up.

 

[Mad_Hatter]

Originally Posted by ZeeOSix
Originally Posted by Mad_Hatter
Originally Posted by ZeeOSix
Originally Posted by Mad_Hatter
I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?

If all factors were held constant in the same exact engine, then running thicker oil would cause the oil to warm-up slightly faster due to more heat generated by the shearing friction. There would have to be a big spread in oil viscosity to see a difference viscosity makes on the oil temp gauge.

Patman's example shows that engine RPM has more impact on oil warm-up time than oil viscosity does.

Agreed.. what I wasn't subscribing to was the notion that running a viscosity thick enough to elicit higher bearing temps, was going to impact engine temps in any meaningful way. Ambient temp, fuel/air mixture, rpms...are all going to have a more profound effect than a thicker oil in the crankcase. Heck, running straight coolant/no water (not something I'd do) would probably do more for accelerating the engine warm up process than a change in viscosity.


Yep ... keep in mind there's a huge difference between how coolant warms up vs how oil warms up.

Right, I get that. But the less efficient the coolant is (by decreasing water%) the more heat retained in the engine, no? Seems to me running a 70/30 in the winter (or even an 80/20) would allow the engine to warm up faster?? (how much & whether it's meaningful is beyond me)...Admittedly I haven't thought though any potential downsides to doing this because as I said, it's not something I personally would ever consider doing.

 

[Bryanccfshr]

Ambient temperatures, all things being equal the cold temperature that the engine reaches influences the warm up time the most,

 

[Shannow]

Originally Posted by Mad_Hatter
Originally Posted by Shannow
Originally Posted by Mad_Hatter

I could be wrong here but I don't think changing the viscosity is going to have a dramatic effect on how fast your engine reaches operating temp. Since oil actually acts like a coolant, no matter what viscosity you run it will do the exact opposite (cool v. heat) of what you're trying to achieve.


No, you are wrong here...

The oil between the bearing surfaces carrries away heat, buit's heat that's generatedin the oilfilm itself...thicker,cooler oil,more RPMmeansmore heat,and faster warmup.

For starters I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?

Maybe some are willing to increase friction at the bearings (& loss of power due to a thicker oil) just to shave a few seconds off warm up..but not me. I'd just as soon give it a little throttle to get things warmed up faster.


You stated that the oil was a coolant...I countered that with what ACTUALLY happens.

Oh, and it's not the "little more throttle", as the heat is related to RPM, not power output.

 

[Shannow]

Originally Posted by DGXR
I don't think cold thick oil will generate enough friction to speed the warmup process when you consider there are EXPLOSIONS taking place in the cylinders.
If cold oil IS generating that much friction, you have much more serious issues than worrying how quickly your engine reaches full temperature.

Also, low ambient temperature is the #1 cause of slow warmup

not thinking is a serious issue these days...

The majority of the heat in the oilis heat generated by the oilitself undergoing shear...not the number of (non)explosions taking place in the cylinder...yes, the (non)explosions make the motive power, but the friction generates most of the heat...

Here's a chart of bearing temperature rise with the engine simply being cranked (zero (non)expolosions)

Here's another couple...showing that the friction due to the oilis highest when the oil iscold and thickest.

and one showing that RPM is far more effective than load for increasing oil temperature.

 

[billt460]

Originally Posted by Shannow
The majority of the heat in the oilis heat generated by the oilitself undergoing shear...not the number of (non)explosions taking place in the cylinder...yes, the (non)explosions make the motive power, but the friction generates most of the heat...

Honest question here. Where I now live is about a 3 mile drive into town..... All downhill. I could literally pull out of my driveway, get the vehicle up to 30 MPH, shift into neutral and not have to touch the gas again until I got to the stoplight at the bottom. (I say that because I've done it in my truck).

When I drive this the car warms up very little. (Both the oil temp gauge, and the coolant temp barely come up at all). If I were to drive the same distance on level ground, the gauges would show considerably warmer engine and oil temp.

So I can't help but think operating the engine under a load will increase oil and coolant temperature much faster. After all you're burning more fuel doing it. That fuel is going to generate heat as it's consumed. That heat is going to be transferred into the oil and the coolant flowing through the engine. Am I right?

 

[Shannow]

bill, the engine in your ecample dropsto idle...the lowest RPM,and lowest load that the engine is capable of doing.

My Caprice with the L67, I could drive the same 6 mile stretch of highway,once in D, the other in "2"...exactly the same road load,wind drag etc...the "2" made 40F more temperature.

 

[billt460]

Originally Posted by Shannow
My Caprice with the L67, I could drive the same 6 mile stretch of highway,once in D, the other in "2"...exactly the same road load,wind drag etc...the "2" made 40F more temperature.

I can buy that. But in "2" it will also be revving higher over the same stretch, and consuming a lot more fuel in the process. How do you isolate one from the other? I buy the whole, "more load = more friction = more heat", deal. But how do you know it's mostly coming from the friction, and not fuel consumption as well? They both go hand in hand.

 

[Shannow]

Originally Posted by billt460
Originally Posted by Shannow
My Caprice with the L67, I could drive the same 6 mile stretch of highway,once in D, the other in "2"...exactly the same road load,wind drag etc...the "2" made 40F more temperature.

I can buy that. But in "2" it will also be revving higher over the same stretch, and consuming a lot more fuel in the process. How do you isolate one from the other? I buy the whole, "more load = more friction = more heat", deal. But how do you know it's mostly coming from the friction, and not fuel consumption as well? They both go hand in hand.


See below...

with engine torque at 10Nm, and 1,000RPM versus 3,000RPM, the difference in oil temperature/warmup is marked.
with same enginespeed, the diffference between 10Nm and 60Nm is little.

So yes, there's more power in the 3,000RPM example, 3 times as much...but in the 60Nm case, there's 6 times as much power, and not a great deal of difference in warmup rate..

In my Caprice example, the oil temperature was 40F ABOVE the coolant temperature.

Patman's example above, was at my recommendation ages ago, and quite a few others are holding lower gears in town to get tempsup for when they hit the on ramp.

Edit...and between figures 6 and 7...
Fig 6, at 800 seconds in, the temperature is about 100C. Dimensionless power is 3,000x10 = 30,000
Fig 7, at 800 seconds in, the temperature is about 90-95C. Dimensionless power is 2,000x60= 120,000

So 4 times more power delivers less energy to the oil..

 

[Mad_Hatter]

Originally Posted by Shannow

You stated that the oil was a coolant...I countered that with what ACTUALLY happens.- this is the 2nd time you've attributed something to me that I didn't say. What I said was, "oil acts like a coolant" and not, "oil is a coolant". It's weird because while the coolant and radiator fulfill the principle role of keeping my engine cool, the oil in my engine also picks up heat as it passes through the engine and let's it go into the atmosphere via the oil cooler. Your oil doesn't function similarly?

Oh, and it's not the "little more throttle", as the heat is related to RPM, not power output. - weird..in my car, whenever I give the engine gas the rpms go up...how does it work in your car?