If all engines at "steady state" and their corresponding temperature control valve(s) achieve temperature with a glycol/water flow then,why would anyone choose a higher weight oil then what is prescribed by the maker, besides the numerous mentioned CAFE? I have a KIA 2005 Sorento, I am thinking of putting in an orphan bottle of 5W50 into a 5w30 engine. Any issues from the crowd?
All Engines Control Temp?
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Originally Posted By: floppy60
all engines once they achieve temperature could be considered at steady state, Yes, some deviations but I would think for the most part engine temp doesnt deviate significantly
Unless you go up or down hill, or drive in 100 degree vs. 0 degree weather, or drive with just yourself or a full load (or even towing)-it deviates a LOT!
all engines once they achieve temperature could be considered at steady state, Yes, some deviations but I would think for the most part engine temp doesnt deviate significantly
Unless you go up or down hill, or drive in 100 degree vs. 0 degree weather, or drive with just yourself or a full load (or even towing)-it deviates a LOT!
My temp. gauge increases noticeably from winter driving to doing a lot of summer stop and go driving, or idling at a stop light just after pulling off the highway...
Oil temps can swing even when the water jacket is stable. Some engines have piston oil squirters to cool things down, that heat has to go somewhere. If there's no oil cooler (air or water) you're counting on the pan giving off heat as air passes over it, and the oil quickly moving over or through parts of the engine kept cool with that steady state thermostatically controlled coolant.
Floppy:
Oil being a fair insulator takes and gives off heat much slower than water. Under continued high stress the oil temps can climb well beyond the coolant temp. Towing/moving heavy loads in high ambient temps or road racing are two big stressors. In your question, you make the case against using the heavy oil then say you want to use it. 1 qt in your sump should pose no issue during spring - fall, I doubt you'll even see a mileage hit.
Oil being a fair insulator takes and gives off heat much slower than water. Under continued high stress the oil temps can climb well beyond the coolant temp. Towing/moving heavy loads in high ambient temps or road racing are two big stressors. In your question, you make the case against using the heavy oil then say you want to use it. 1 qt in your sump should pose no issue during spring - fall, I doubt you'll even see a mileage hit.
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I don't think climbing oil temps is due to oil being an "insulator", it's because the whole front of the vehicle isn't equipped with an oil-to-air radiator like it is for coolant...
I'm puzzled why you feel oil is an insulator. They use oil as coolant in transformers and many other applications, and I believe I read here about someone using diesel as coolant in their road vehicle (not that I'd recommend it).
I'm puzzled why you feel oil is an insulator. They use oil as coolant in transformers and many other applications, and I believe I read here about someone using diesel as coolant in their road vehicle (not that I'd recommend it).
I was talking to my buddy the other day and he races stock cars, pure stock and he told me that when they are pounding the cars on the dirt track, his exhaust will glow cherry red, but his water temps are staying cool, he changes oil every two weeks and uses Valvoline 20w50 and tells me he might go to straight 50wt, because when he drains the oil it is Black and smells burnt. Now I understand that is racing dirt track and we never do that to our cars, our teenage children might, but it tells me that this therory that lighter oils are fine because they are in a temperature controlled enviroment is [censored] and oil temps can rise without reflecting water temps.
How are drivers measureing coolant temperature? Most guages function as 'idiot lights' and point to 210F anytime the temperature is between 180F and 235F. Older cars seem to show a lot more variation on the temperature guages due to outside temperatures.
Coolant temperature and oil temperature are different.
Oil temp is very much more related to ambient temperatures and engine conditions.
Oil temp is very much more related to ambient temperatures and engine conditions.
Originally Posted By: Craig in Canada
... I'm puzzled why you feel oil is an insulator. They use oil as coolant in transformers and many other applications, and I believe I read here about someone using diesel as coolant in their road vehicle (not that I'd recommend it).
Craig, I dont "feel" oil is an insulator - it is, and you just gave an example in the xformer. Water is pretty unique in it's capacity for heat vs other fluids. But, most any fluid in contact with a heat source will absorb and transfer some heat energy and would be prefered over "air" or a vacuum. AFA transformers go - I think paraffins would be prefered over H-O-H and possibly Krytox over paraffins in some apps
... I'm puzzled why you feel oil is an insulator. They use oil as coolant in transformers and many other applications, and I believe I read here about someone using diesel as coolant in their road vehicle (not that I'd recommend it).
Craig, I dont "feel" oil is an insulator - it is, and you just gave an example in the xformer. Water is pretty unique in it's capacity for heat vs other fluids. But, most any fluid in contact with a heat source will absorb and transfer some heat energy and would be prefered over "air" or a vacuum. AFA transformers go - I think paraffins would be prefered over H-O-H and possibly Krytox over paraffins in some apps
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Thermal conductivity (K) of some materials:
Glass = 1, Pine = 0.2, Oil = 0.2, Water = 0.6, Aluminum = 215
Note that heat capacity is a big factor in coolants; Ammonia is rather good and gets better as it is heated. Straight ethylene gly and mineral oil are about equal (and MUCH worse than water).
Glass = 1, Pine = 0.2, Oil = 0.2, Water = 0.6, Aluminum = 215
Note that heat capacity is a big factor in coolants; Ammonia is rather good and gets better as it is heated. Straight ethylene gly and mineral oil are about equal (and MUCH worse than water).
Specific heat of water = 1
specific heat of oil ~ 0.4
It takes only 40% as much energy to heat oil 1 degree compared to water.
The fact that oil has a lower conductivity is IMHO irrelevant, lube oil is massively and quickly exposed to the engine's internal heat production and quickly reflects the mean internal temp of the engine.
Charlie
PS I don't think one bottle of 5W50 will hurt anything in a Kia Sorrento; just a subjective opinion
specific heat of oil ~ 0.4
It takes only 40% as much energy to heat oil 1 degree compared to water.
The fact that oil has a lower conductivity is IMHO irrelevant, lube oil is massively and quickly exposed to the engine's internal heat production and quickly reflects the mean internal temp of the engine.
Charlie
PS I don't think one bottle of 5W50 will hurt anything in a Kia Sorrento; just a subjective opinion
Use the odd qt. of oil .
Originally Posted By: floppy60
all engines once they achieve temperature could be considered at steady state, Yes, some deviations but I would think for the most part engine temp doesnt deviate significantly
Depends upon the loading of the engine.
all engines once they achieve temperature could be considered at steady state, Yes, some deviations but I would think for the most part engine temp doesnt deviate significantly
Depends upon the loading of the engine.
Doesn't anyone have any HIGH powered engines?
Big V-8's can spike 10-20 degrees just by flooring the throttle in a higher gear for 10 to 15 seconds!
Just depends where your temp sensor is located and the resolution of your display!
Big V-8's can spike 10-20 degrees just by flooring the throttle in a higher gear for 10 to 15 seconds!
Just depends where your temp sensor is located and the resolution of your display!
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