Nessmuk
Well-Known Member
Is it possible to have to much oil cooling in a diesel running 15-40 rotella?
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Can oil be over cooled?
- Thread starter Nessmuk
- Start date
79jasper
Active Member
Imo, on a 6.5, not really.
Say on a heui engine, you don't want it too hot, but you don't want it cold either.
Sent from my SAMSUNG-SM-G935A using Tapatalk
Say on a heui engine, you don't want it too hot, but you don't want it cold either.
Sent from my SAMSUNG-SM-G935A using Tapatalk
Will L.
Well-Known Member
There is not a ton I remember from the oil engineers I used to work with, but here is what I committed to memory...
15w40. The w is winter, not weight. 15 winter (or cold) 40 nominal.
Temperature of oils is 1,2,3. 1=100,2=200,3=300 f.
At 100 degrees it is 40 weight. The 15 winter rating is just to get it up to temp. It can operate in the lower temps, but that is not where it performs the best. It is just dealing with the cold the best it can. That is the winter rating. Like running kerosene intead of diesel to cope with winter- works but not what is desirable.
At 200 degree (ok, actually 212 at sea level, so boiling off water) it is performing at peak efficiency. That is where all oil is spec'd at and has it's best lubricative balance.
At 300 it is being destroyed. You can actually crack some of the fines in the molecular chain at 327f at sea level. In other words, literally disassembling the oil.
We were going over "perfect world scenarios". Install a stick on pan heater and warm the oil to 212f before turning on the external oilpump to pressurize the system before starting the engine. Then cool any oil that gets to 225. All this being on a straight weight oil.
Oil blends help make up for imperfect items like weather. But they do give up performance to do so.
Keep the oil above 100f all the time you are driving, but just a hair above the temperature that water boils at in your area is ideal. Keep in mind, when centrifuging any oil, that is the temperature it always works best at.
Next week: why spark plugs are for suckers...
15w40. The w is winter, not weight. 15 winter (or cold) 40 nominal.
Temperature of oils is 1,2,3. 1=100,2=200,3=300 f.
At 100 degrees it is 40 weight. The 15 winter rating is just to get it up to temp. It can operate in the lower temps, but that is not where it performs the best. It is just dealing with the cold the best it can. That is the winter rating. Like running kerosene intead of diesel to cope with winter- works but not what is desirable.
At 200 degree (ok, actually 212 at sea level, so boiling off water) it is performing at peak efficiency. That is where all oil is spec'd at and has it's best lubricative balance.
At 300 it is being destroyed. You can actually crack some of the fines in the molecular chain at 327f at sea level. In other words, literally disassembling the oil.
We were going over "perfect world scenarios". Install a stick on pan heater and warm the oil to 212f before turning on the external oilpump to pressurize the system before starting the engine. Then cool any oil that gets to 225. All this being on a straight weight oil.
Oil blends help make up for imperfect items like weather. But they do give up performance to do so.
Keep the oil above 100f all the time you are driving, but just a hair above the temperature that water boils at in your area is ideal. Keep in mind, when centrifuging any oil, that is the temperature it always works best at.
Next week: why spark plugs are for suckers...
schiker
Well-Known Member
A couple big variables- commute time, ambient temps, humidity, load and what you need oil to do ? Lube and or help cool.
I can see winter time in cold weather short commute being cooled too much. Short commute being hard on any real cold temps. Might also vary with humidity. Heard of a dodge v6 for short commutes getting some condensation-cooled blowby show some milky color on filler mouth. Again it was related to short commute.
Ideal viscosity and efficiency a little aside ....
For the 6.x operating above 40F if it gets to operating temps for more than 15 min? NO you can't cool it too much. I use to think oil needed to get over 212F to boil off all condensation but I think thermostat temp is warm enough. It will still get hot enough locally to flash off condensation vs. with oil avg temp much over thermostat temp or over 215F it's adding load to the radiator and getting really hot in some locations. So anywhere in 170F to 190F would be good for the 6.x cooler the better for high loads warmer ok for light loads. A oil thermostat at 170f would be great as long as it was always circulating some and didn't cold dump .
I can see winter time in cold weather short commute being cooled too much. Short commute being hard on any real cold temps. Might also vary with humidity. Heard of a dodge v6 for short commutes getting some condensation-cooled blowby show some milky color on filler mouth. Again it was related to short commute.
Ideal viscosity and efficiency a little aside ....
For the 6.x operating above 40F if it gets to operating temps for more than 15 min? NO you can't cool it too much. I use to think oil needed to get over 212F to boil off all condensation but I think thermostat temp is warm enough. It will still get hot enough locally to flash off condensation vs. with oil avg temp much over thermostat temp or over 215F it's adding load to the radiator and getting really hot in some locations. So anywhere in 170F to 190F would be good for the 6.x cooler the better for high loads warmer ok for light loads. A oil thermostat at 170f would be great as long as it was always circulating some and didn't cold dump .
schiker
Well-Known Member
In stock trim there is no oil thermostat. EPA may eventually force one if we don't run water viscosity first.
A progressive thermostat would be nice for both coolant and oil. Maybe I think oil is more forgiving if you orifice the loops both constant flow loops it should not excessively shock. As it warms and thins more will push thru cooler as cooler warms more flow too. That's about how it works now but with a spring loaded bypass - offset for extreme cold not thermostatically controlled.
A progressive thermostat would be nice for both coolant and oil. Maybe I think oil is more forgiving if you orifice the loops both constant flow loops it should not excessively shock. As it warms and thins more will push thru cooler as cooler warms more flow too. That's about how it works now but with a spring loaded bypass - offset for extreme cold not thermostatically controlled.
In depth Military, taxpayer funded, low oil temperature study is truly the final word and in respect to this engine. Yes, they looked at nearly as cold as it can get... Yes, you should relocate the OPS per their recommendation.
http://www.thetruckstop.us/forum/th...bility-in-a-6-2-internal-oil-flow-info.41477/
http://www.thetruckstop.us/forum/th...bility-in-a-6-2-internal-oil-flow-info.41477/
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Will L.
Well-Known Member
Understand, the 212 temp is not the best because it boils off the water.
Most oils simply lubricate the best at that temperature, so that is the preferred temperature range. Most synthetics actually prefer a touch higher- counter intuitive I know, but science doesnt care what is convenient.
While the test WarWagon posted is very helpful to show how bad soot screws with viscosity, especially at low temps, notice they did not do friction tests.
The move the ops suggestion was one of many they ignore. Move temp sensor to passenger rear head, No ect over 220, collapsible steering columns, airbags, blah blah blah.
Since oil is hydrophobic, it isnt hard to get water out of oil. Truth is water actually seperates best at 195 from any hydrocarbon liquid while it is still a liquid itself. Once it goes vapor, it starts trying to mix in again. If anyone has a noteable humidity/ moisture issue in their crankcase, it needs to be addressed separately. Just boiling the water does nothing to help. The vapors simple cool and condense repeatedly causing havoc everytime they hit metal. Get it out, and keep it out.
Quit thinking "the mfr did it this way, so it's the best way". They only screw up the stuff the touch.
"But Will, GM is #1 and does everything perfectly". Yes they do- enjoy your paint jobs- still the worst since 1970's...
Oil companies have been trying like hell to get mfrs to regulate oil temps properly. But why would they want engines to last so much longer when you can just buy a new car?
As for the oil cooling of the super heat an engine supplies- no. Get a cast iron skillet and put it on the stove. Get it to 200, then time it cooling off. Then do it again with oil in it- maybe cooking oil if the wife is home. And watch the time. Then some water. Yeah- oil is temperature control, but usually so that it keeps the temperature from cooling quickly. Oil is used for thermal regulation industrially, not for cooling, because it is not a great conductor. Transmission fluid does well because of the friction modifying metals that are added. Do the same test with 10 weight oil vs atf (rated at 10 weight). The atf will cool it off in almost half the time. Its not the oil cooling your trans, it is the crap in the oil.
Think about evans waterless as another example- swapping antifreeze for evans, and you normal operating temps are higher because the super light weight oil, even with its additives, can not transfer heat as fast.
Oil will cool, but engine oil should in no way be considered a way to shed engines heat- that needs to remain the job of the coolant. Oil coolers are needed usually because coolant systems under perform.
Most oils simply lubricate the best at that temperature, so that is the preferred temperature range. Most synthetics actually prefer a touch higher- counter intuitive I know, but science doesnt care what is convenient.
While the test WarWagon posted is very helpful to show how bad soot screws with viscosity, especially at low temps, notice they did not do friction tests.
The move the ops suggestion was one of many they ignore. Move temp sensor to passenger rear head, No ect over 220, collapsible steering columns, airbags, blah blah blah.
Since oil is hydrophobic, it isnt hard to get water out of oil. Truth is water actually seperates best at 195 from any hydrocarbon liquid while it is still a liquid itself. Once it goes vapor, it starts trying to mix in again. If anyone has a noteable humidity/ moisture issue in their crankcase, it needs to be addressed separately. Just boiling the water does nothing to help. The vapors simple cool and condense repeatedly causing havoc everytime they hit metal. Get it out, and keep it out.
Quit thinking "the mfr did it this way, so it's the best way". They only screw up the stuff the touch.
"But Will, GM is #1 and does everything perfectly". Yes they do- enjoy your paint jobs- still the worst since 1970's...
Oil companies have been trying like hell to get mfrs to regulate oil temps properly. But why would they want engines to last so much longer when you can just buy a new car?
As for the oil cooling of the super heat an engine supplies- no. Get a cast iron skillet and put it on the stove. Get it to 200, then time it cooling off. Then do it again with oil in it- maybe cooking oil if the wife is home. And watch the time. Then some water. Yeah- oil is temperature control, but usually so that it keeps the temperature from cooling quickly. Oil is used for thermal regulation industrially, not for cooling, because it is not a great conductor. Transmission fluid does well because of the friction modifying metals that are added. Do the same test with 10 weight oil vs atf (rated at 10 weight). The atf will cool it off in almost half the time. Its not the oil cooling your trans, it is the crap in the oil.
Think about evans waterless as another example- swapping antifreeze for evans, and you normal operating temps are higher because the super light weight oil, even with its additives, can not transfer heat as fast.
Oil will cool, but engine oil should in no way be considered a way to shed engines heat- that needs to remain the job of the coolant. Oil coolers are needed usually because coolant systems under perform.
schiker
Well-Known Member
I see your point about vapor mixing with oil and oil is slower to transfer heat etc BUT in a turbo diesel oil does help cool the piston. Coolant doesn't touch piston only air and oil.
Yes, it's too slow for indicator in most all applications except sustained heavy loads. Stationary equipment, towing heavy long grades, wind drag or Marine etc.
Mostly over heated oil will shorten its life not harm the engine. Cooling the oil can help shed excessive heat and help other indicators.
Yes, it's too slow for indicator in most all applications except sustained heavy loads. Stationary equipment, towing heavy long grades, wind drag or Marine etc.
Mostly over heated oil will shorten its life not harm the engine. Cooling the oil can help shed excessive heat and help other indicators.
Nessmuk
Well-Known Member
Turbo and piston cooling are my major concerns. I change my oil more often then needed actually.
schiker
Well-Known Member
Letting piston and oil get over heated for more than 20 minutes and then cooling too quickly is probably more dangerous than pushing limits for 5 minutes. ???? Coolant can cool cylinder wall too quickly and scuff a piston once major load is removed.
Depends on how high the temp gets and how long. Overheated oil can turn to sludge and clog up the oil pump screen and sludge still happens to this day in some engines. Google Oil Sludge for many cases of this in hot running engines causing engine failure. At a specific temperature oil simply fails and you scuff pistons. Piston cooling nozzles are "oil cooling". The biggest cooling of oil is from the thin oil pan. Oil coolers are only added when the OEM has no other choice. Corvette is famous for Synthetic Factory oil fill. Not because of the no-compromise marketing: it's because GM was too fing cheap to put an oil cooler on it and synthetic was the only oil that could stand the high temps. Synthetic factory fill is way cheaper than an oil cooler and related warranty on GM's low temperature rated oil cooler lines that constantly overheat and leak/fail.
Oil cooling is not the best way to cool things, but, one needs to keep the temperatures under control including power steering oil temps.
Working hard the hot heads and valve cover CDR system suck out 1 quart of oil every 500 miles for me. GM used the hottest head. Maybe vaporizing and burning the oil was GM's second way to cool the passenger head...
Nessmuk
Well-Known Member
Always wanted case aluminum heads and oil pan with fins.
schiker
Well-Known Member
Yeah, engine compartment temps and air temps over thin metal areas matter. Air flow over valve covers, oil pan, and oil filter cool the oil some.
I think the upper sustained average temperature of Dino oil is around 248F or 256F with intermittent temps to 266F for Kubota, Yanmar, & Deutz. This is for standard maintenance schedule engine application approval test not a hard limit for oil temperature.
In my mind when IAT or oil temp get above 215 -220 F they are still cooling the super heat of combustion ~ 1000 + F (most of which goes out exhaust pipe). And they are still well below danger temps for themselves but are now adding more load to the coolant that we don't want above 215F instead of helping keep ect below 215F.
I agree oil should not be dependended on to cool but I do see it as a component in the cooling.
I think the upper sustained average temperature of Dino oil is around 248F or 256F with intermittent temps to 266F for Kubota, Yanmar, & Deutz. This is for standard maintenance schedule engine application approval test not a hard limit for oil temperature.
In my mind when IAT or oil temp get above 215 -220 F they are still cooling the super heat of combustion ~ 1000 + F (most of which goes out exhaust pipe). And they are still well below danger temps for themselves but are now adding more load to the coolant that we don't want above 215F instead of helping keep ect below 215F.
I agree oil should not be dependended on to cool but I do see it as a component in the cooling.
consaka
Active Member
After doing some tests recently I have come to the conclusion that oil temp may be more important then most people realize. Consider that heating a piston to 270F on a 60 degree day seizes it in the cylinder. What is happening under the piston is as important as what is happening above it.
There is a constant heat transfer battle going on and the fight is for your pistons. Above you have massive amounts of heat. Below you have the cooling. Something I read said almost a third of the piston cooling comes from oil slinging around absorbing and transferring heat. Oil also acts as the interface and transfer of heat between the skirt and the cylinder wall. If the piston is not cooled off enough it will seize in the cylinder. That happens pretty quick if your engine runs out of oil.
I'd get nervous if I was working it hard and the temps started to climb to the 300 area. 170 for my current engine considering it has no oil pressure hot at idle. lol
There is a constant heat transfer battle going on and the fight is for your pistons. Above you have massive amounts of heat. Below you have the cooling. Something I read said almost a third of the piston cooling comes from oil slinging around absorbing and transferring heat. Oil also acts as the interface and transfer of heat between the skirt and the cylinder wall. If the piston is not cooled off enough it will seize in the cylinder. That happens pretty quick if your engine runs out of oil.
I'd get nervous if I was working it hard and the temps started to climb to the 300 area. 170 for my current engine considering it has no oil pressure hot at idle. lol
Will L.
Well-Known Member
Yeah, I should have qualified that 300. Oil dies there. Engines die way before there. Kinda like coolant can stay alive at 320, but your engine will be toast.
Nessmuk
Well-Known Member
My little truck has that no pressure when hot thing. Been looking at a cooler for it too.
consaka
Active Member
I should have actually answered my belief of the question. Can you overcool oil? Sure you can. Oil that is too cool is most likely bypassing the filter. I think it would take a lot to cool the oil down too much especially in summer. Keep in mind the viscosity of oil creates heat. When it is cold tight tolerances create a lot of heat.
One of the reasons you aren't supposed to rev a cold engine has to do with how fast the cold oil can get to those bearings. Heated oil leaves quickly. I am always a bit concerned that the resistance on the bearings might spin a weaker or compromised bearing. Pretty sure most spun bearings actually spun while the engine was cold.
One of the reasons you aren't supposed to rev a cold engine has to do with how fast the cold oil can get to those bearings. Heated oil leaves quickly. I am always a bit concerned that the resistance on the bearings might spin a weaker or compromised bearing. Pretty sure most spun bearings actually spun while the engine was cold.
SmithvilleD
Active Member
A decade ago when I rebuilt my 6.5, I replaced the stock oil cooler with a larger 48 stacked plate (36 stock I believe) oil cooler. And I've got oil temp, oil pressure, and ECT gauges. Having both oil temp and pressure gauges really illustrates how much viscosity & oil pressure varies with oil temp.
In summer temps there isn't any issue with oil not coming up to and maintaining 200 degree temps under low engine loads. Under intermittent heavy loads the engine coolant temp would go too high quicker than oil temps getting out of hand.
Midwest winter temps are another story entirely. In cold winter temps, it's quite possible to over cool the engine oil. In 10 degree winter temps, my oil temp runs too cool when the truck's loafing along unloaded. It's not uncommon for me to see steady state (rolling empty down the highway) oil temps well under 150 degrees - the colder it gets, the worse it is.
Not thinking imminent engine harm; just oil temp running well below temps the oil works best at - and slowing the rate of driving the water out - that condensed in at last shutdown/cool down. I've got an oil temp thermostat, but have yet to sort out a suitable packaging/hose routing.
For gaining overall heat shedding capability for summertime towing, I think relocating the oil cooler out of the radiator cooling stack showed the most benefit. Maybe a little from the oil cooler getting its own air stream, but mostly from the section of radiator that used to be behind the oil cooler now sees ambient air temps and now that rad section sheds more heat.
In summer temps there isn't any issue with oil not coming up to and maintaining 200 degree temps under low engine loads. Under intermittent heavy loads the engine coolant temp would go too high quicker than oil temps getting out of hand.
Midwest winter temps are another story entirely. In cold winter temps, it's quite possible to over cool the engine oil. In 10 degree winter temps, my oil temp runs too cool when the truck's loafing along unloaded. It's not uncommon for me to see steady state (rolling empty down the highway) oil temps well under 150 degrees - the colder it gets, the worse it is.
Not thinking imminent engine harm; just oil temp running well below temps the oil works best at - and slowing the rate of driving the water out - that condensed in at last shutdown/cool down. I've got an oil temp thermostat, but have yet to sort out a suitable packaging/hose routing.
For gaining overall heat shedding capability for summertime towing, I think relocating the oil cooler out of the radiator cooling stack showed the most benefit. Maybe a little from the oil cooler getting its own air stream, but mostly from the section of radiator that used to be behind the oil cooler now sees ambient air temps and now that rad section sheds more heat.
guybb3
Member
How about running a Winter Front during the colder months?
SmithvilleD
Active Member
Yep, that's been the practical solution for now - covering, restricting airflow.
My oil cooler is mounted behind a perforated stock skid plate, and the fan is thermostat controlled. The oil cooler thermostat would also help oil come up to temp faster, but there's not a lot of space to plumb it in. Need a place where the hoses run parallel for a ways to splice thermostat in.
