Oil viscosities at 200 to 225 F

Status
Not open for further replies.
S

Snagglefoot

Joined
Dec 31, 2017
Messages
15,314
Location
SE British Columbia, Canada
We just went through a forum discussion of measured oil temperatures. I think generally it was found that temps can get up to just short of 225 F and normal operating coolant temps in modern engines are around 200 to 210 F.

Does anyone have any data of the kinematic viscosities of oil at temps higher than the normal Kv100 ( 100 C or 212 F)?

I ask this because the Kinematic viscosity values flatten out once temps are at 212 F. I'm going to venture there is very little kinematic viscosity difference between an oil at 210 F vs 225 F. Can anyone offer up some data? Thanks.
smile.gif
 
Originally Posted by Snagglefoot

Originally Posted by OVERKILL
A visc calc should work properly at those temperatures, I'd just use that.


OK. Let's do one.


OK, what oil do you want to do? The example for a 5w-30 on Widman's site has the following characteristics:
40C: 62.5cSt
100C: 10.4cSt

105C: 9.4cSt
110C: 8.5cSt
115C: 7.7cSt
120C: 7.0cSt
125C: 6.5cSt
 
Unless the equations contain the exact coefficients of the specific VII, base oil used, and the additives used, don't count on this as being accurate.
 
Originally Posted by Snagglefoot
That's good data. More of a change than I expected. Thanks.
smile.gif



Yep, enough change to undetstand why using a 30 or 40 weight oil at higher oil temperatures makes a difference in engine protection by providing a higher MOFT due to the higher viscosity.
 
Originally Posted by MolaKule
Unless the equations contain the exact coefficients of the specific VII, base oil used, and the additives used, don't count on this as being accurate.


For sure, I think it's sufficient for demonstrating the trend though. Same thing comes into play when folks try and extrapolate cold temp performance the same way.
 
I ran my Grand Cherokee through the mountains between 12,000 and 14,000 ft above sea level a few weeks ago, with my oil and water temps at 110ºC (230ºF) most of the day. No oil consumption on that 280 km trip (actually only down ⅛" in 8000 km). When it comes time to change oil, I'll send it in. But I run a PAO based 5W-30. Jeep started out with 5W-30 in 2011 and 2012, then changed their recommendation to 5W-20 for some reason.

Ambient temps were 15ºC (50ºF) most of the day, although I still get 108ºC on these drives when the ambient temp is below freezing, and snowing.
 
Originally Posted by ZeeOSix
Originally Posted by Snagglefoot
That's good data. More of a change than I expected. Thanks.
smile.gif



Yep, enough change to undetstand why using a 30 or 40 weight oil at higher oil temperatures makes a difference in engine protection by providing a higher MOFT due to the higher viscosity.


Also why I cringe when I hear about people taking their cars racing and thinking 300+°F oil temps are fine because their "oil can take it". The engine would be the better question to ask for sure.
 
I built and maintain a couple engines that use a dry sump oiling system. One of those engines is in a dirt Late Model that makes peak horsepower at 8300-8500 rpm and runs between 7500-9000 rpm for 100 laps or more. Even with an oil cooler, it's not uncommon for oil temps to reach 280+*F. We ran Valvoline VR1 20w-50 in it for a couple years until we started having oil pressure issues and eventually lost a dry sump pump. We put it on a dyno and ran it hard like it would be at the track and watched the oil closely. What we found was a lot of aeration, tons of bubbles in the oil tank, that increased with heat and rpm. We switched the engine over to Red Line 5w-50 and much of that aeration subsided, along with the average oil temp coming down about 10*F.

Despite all of that though, the guts all showed little wear when I tore it down after the pump failure.
 
Originally Posted by widman
I ran my Grand Cherokee through the mountains between 12,000 and 14,000 ft above sea level a few weeks ago, with my oil and water temps at 110ºC (230ºF) most of the day. No oil consumption on that 280 km trip (actually only down ⅛" in 8000 km). When it comes time to change oil, I'll send it in. But I run a PAO based 5W-30. Jeep started out with 5W-30 in 2011 and 2012, then changed their recommendation to 5W-20 for some reason.

Ambient temps were 15ºC (50ºF) most of the day, although I still get 108ºC on these drives when the ambient temp is below freezing, and snowing.

The 3.6L runs hot, with those temps I'd be running 5W30 as well, which I do.
 
Originally Posted by OVERKILL
Originally Posted by MolaKule
Unless the equations contain the exact coefficients of the specific VII, base oil used, and the additives used, don't count on this as being accurate.


For sure, I think it's sufficient for demonstrating the trend though. Same thing comes into play when folks try and extrapolate cold temp performance the same way.

+1.
The general usefulness/applicability of Widman viscosity tool is beyond a doubt, even to an oil industry 'professional' if I may add.
 
Originally Posted by RDY4WAR
I built and maintain a couple engines that use a dry sump oiling system. One of those engines is in a dirt Late Model that makes peak horsepower at 8300-8500 rpm and runs between 7500-9000 rpm for 100 laps or more. Even with an oil cooler, it's not uncommon for oil temps to reach 280+*F. We ran Valvoline VR1 20w-50 in it for a couple years until we started having oil pressure issues and eventually lost a dry sump pump. We put it on a dyno and ran it hard like it would be at the track and watched the oil closely. What we found was a lot of aeration, tons of bubbles in the oil tank, that increased with heat and rpm. We switched the engine over to Red Line 5w-50 and much of that aeration subsided, along with the average oil temp coming down about 10*F.

Despite all of that though, the guts all showed little wear when I tore it down after the pump failure.


I should have been more specific in stating that I was referring to OEM vehicles being run at the track with OEM street viscosity.

But yes, a properly built engine with a high HTHS oil can survive some noteworthy extremes.

Pretty interesting that VR1 wasn't holding up. Very unexpected.
 
Originally Posted by demarpaint
Originally Posted by widman
I ran my Grand Cherokee through the mountains between 12,000 and 14,000 ft above sea level a few weeks ago, with my oil and water temps at 110ºC (230ºF) most of the day. No oil consumption on that 280 km trip (actually only down ⅛" in 8000 km). When it comes time to change oil, I'll send it in. But I run a PAO based 5W-30. Jeep started out with 5W-30 in 2011 and 2012, then changed their recommendation to 5W-20 for some reason.

Ambient temps were 15ºC (50ºF) most of the day, although I still get 108ºC on these drives when the ambient temp is below freezing, and snowing.

The 3.6L runs hot, with those temps I'd be running 5W30 as well, which I do.


Interesting note, last week I had to go over to the border with Brazil for a day, so ran the 400 miles each way at 100 mph (except in traffic and toll booths), with ambient temps of 94ºF and engine temps of 92ºC (198ºF). The transmission that runs 92ºC in the mountains ran at 74ºC.
 
Originally Posted by RDY4WAR
I built and maintain a couple engines that use a dry sump oiling system. One of those engines is in a dirt Late Model that makes peak horsepower at 8300-8500 rpm and runs between 7500-9000 rpm for 100 laps or more. Even with an oil cooler, it's not uncommon for oil temps to reach 280+*F. We ran Valvoline VR1 20w-50 in it for a couple years until we started having oil pressure issues and eventually lost a dry sump pump. We put it on a dyno and ran it hard like it would be at the track and watched the oil closely. What we found was a lot of aeration, tons of bubbles in the oil tank, that increased with heat and rpm. We switched the engine over to Red Line 5w-50 and much of that aeration subsided, along with the average oil temp coming down about 10*F.

Despite all of that though, the guts all showed little wear when I tore it down after the pump failure.


A good read, thanks for sharing. Sometime interesting posts on here go unappreciated
 
Status
Not open for further replies.

Similar threads

F
Viscosities at different temps
Replies
8
Views
964
FMC
F
I Would Like to Try a 5W30 in my 2022 Pathfinder
2 3
Replies
46
Views
5K
CKN
Ruturaj
Looking for oil for Subaru BRZ with FA24D
2 3 4
Replies
61
Views
5K
Jasperino
RDY4WAR
Engine Masters (MotorTrend) Tests Oil Viscosity (Thickies Rejoice!)
2 3
Replies
46
Views
9K
DavidJones
F
Choosing Oil Weight Based on Actual Engine Temps
Replies
12
Views
2K
weaponoffreedom
Back
Top