Oil Weight vs Warm Up Time

[SpitfireS]

Originally Posted By: Familyguy

I see where this is headed....

I disagree!

To add some fuel to this fire:
What warms up faster in an engine: coolant or oil?
Why?

 

[Gary Allan]

Originally Posted By: Jaymus
Well, what have we concluded?

Will a thicker oil in an engine hit a higher temperature faster than a thinner oil? Or will it practically be equal?

How about when they are both at, say, 50F? Would the thicker oil somewhat warm a noticeable amount faster until they get to, say, the 120F degree range?

I wonder because I use 5W-40 Rotella-T Synthetic, and it would be nice to know it's thinning down somewhat quickly, especially with winter coming on. I hope this will be a good winter oil for my truck, because I want the oil for the extra Zinc/Phosphorous, and I like the 40 weight because I work my truck. I don't want an oil that's too thick for the winter, though. I have an 86 F-150 5.0 EFI flat tappet. I just want what's best for it (That doesn't break the bank, either )



Basically you can swap the viscosity of your choice for differing ambient temps. While the normalized temp may drift a bit, the time to temp is about the same. The curve is very steep initially ..then tapers off. Exchanged engines tend to heat about 30% sooner ..assuming the sump isn't like 8 quarts.

 

[labman]

Originally Posted By: Gary Allan
Originally Posted By: labman
Originally Posted By: Gary Allan
The smaller tubes add up to more surface area. That is, 1x8 tube can fit nearly 50 1" tubes within it. Much more surface area.


No, a bigger tube would have more surface area. The closer the oil is to the wall of the tube, the more it cools. I am amazed that a simple, well know principle of the surface to mass ratio needs to be explained.


Help me out again, labman.


Some tasks are beyond me.

 

[labman]

Originally Posted By: Jaymus
I'm really curious to an answer for my question.

It would make me feel a little better about running the RTS 5W-40 that I run. Just to know that my cst is dropping closer to operating cst quickly.

Like, if both lines were on a graph, of 5W-40 and 5W-20.. both of them heating up to 100C. It seems like common sense that the downward curve of the 5W-40 would, of course, have a steeper curve than the 5W-20. At the same time, 5W-20, I'm sure, will reach it's operating temperature cst sooner.

But, what I worry is that 5W-40 is staying too thick or something until warm up. But, I'm hoping that, really, since it's thicker, it's heating up faster, getting closer to the low cst that my engine needs.


Both should start out near the same viscosity. As it heats up, the 40 weight should start to be thicker than the 20 weight. I think the 20 weight will heat faster because it will be thinner and flow better. Thus it would reach its operating viscosity sooner.

Originally Posted By: Jaymus

But, what I worry is that 5W-40 is staying too thick or something until warm up. But, I'm hoping that, really, since it's thicker, it's heating up faster, getting closer to the low cst that my engine needs.

I drive a 5.0 EFI with 125,000 miles on it. Low mileage in my eyes, but I think it's fine with a 40 weight anyways, it mainly has just be having my curiosity. The sad part is, I can't put my question into proper words. Mainly because of this baby running around..


And btw, do you think RTS 5W-40 is going to be ok for winter in east Tennessee. Let's say the average lows are 10-20F. It should be fine, right? Even if it actually got single digits, it should be ok? I use it because my flat tappet 5.0 EFI is in a truck, and I haul wood, tow vehicles sometimes... just generally work my truck. And when I 4x4, I do raise [censored]. So, I like the idea of extra z/p for the way I use my truck. That's why I use an HDEO, and I use a synthetic version for the 5W-xx rating. And Jaymus isn't my real name... so don't think I'm a stupid hick, lol.


Since both start as a 5W, either should give good flow when cold. At intermediate and operating temperature it gets into the the old thick vs thin debate I am not competent to settle. With a good cooling system, the operating temperature and viscosity should be nearly the same in any weather. So the 40 weight should be no worse in the winter than the summer.

 

[labman]

Originally Posted By: SpitfireS
Originally Posted By: Familyguy

I see where this is headed....

I disagree!

To add some fuel to this fire:
What warms up faster in an engine: coolant or oil?
Why?


I have no data that would take all the fun out of it. I say the thinner water with better heat transfer. I could be wrong. There is more of it, and it has a higher heat capacity. Heat will transfer to it faster, but it will take more. It is kind of which is faster to 60, a small car with a small engine, or a big car with a big engine.

 

[IndyIan]

Originally Posted By: Jaymus
Yeah, I'm mainly wondering which oil, in the same car, between a 5W-40 and 5W-20, both starting at 0 degrees F, would hit, say, 150 degrees F first.

That's my main question in the best I can word it.

In theory at 0F they are both 5 weight oils so I'd think they'd gain temperature about the same initially atleast.

I still have 15W40 in my cars and overnight temps are getting into the 30-40F range and although both start as normal, I wonder if the extra work the engine has to do to run the oil pump is helping the engine and therefore oil get up to temperature sooner?
I'm waiting for some synthetic 5W? or 0W? comes on sale to do the oil changes for the winter but I'm running out of time.
There is some old 0W30 rotella T semisynthetic at a hardware store nearby which I might get if nothing comes on sale soon...

 

[Gary Allan]

Originally Posted By: IndyIan
I wonder if the extra work the engine has to do to run the oil pump is helping the engine and therefore oil get up to temperature sooner?



Quote:
The heavier (at the moment - there's that dynamic view there) oil will take more energy to pump and shear


It will demand more hp (due to added load) to pump it ..and the heavier oil will have more internal friction in shearing ..self generated heat.

The condition is somewhat self correcting.

 

[Gary Allan]

btw-for those of unforgiving nature ..substitute the proper "circumference" where diameter was used (back there somewhere). Brain "emissions".

 

[SpitfireS]

Are there oil company's that advertise with
"

Reduced Warm-up Time And Reduced Warm-up Wear!

"?

IOW, if oil A would do better than oil B, oil A would make sure everybody knows.. right?
I could not find anything in the ACEA spec about warm-up time.

Oh well...

 

[Gary Allan]

The marketing term is:

90% of all wear occurs at start up!" ..without telling you that startup is about the first 20 minutes of operation.