So I've recently been using 10w60 in my high mileage, beat to heck Accent, and out of curiosity I decided to see what the oil temperature was during my long commute, and to my surprise I never saw higher than 208°F, even on the highway it was averaging around 200°. Car doesn't have an oil to coolant heat exchanger, and it's not uncommon to see 220-230° from normal driving using 5w-30 or 0w-40. Conventional wisdom says thicker oil should run hotter due to viscous drag, what gives?
Thicker oil=lower oil temps?
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I just wonder what 10w60 ??? Who makes that? Castrol??
Motul 8100. The Castrol is pretty lame.
No, thicker oil will retain heat longer and also heat up at a faster rate.
How does thicker oil retain heat longer?
You should probably look into the stribek curve. Too thin or too thick can both increase friction and heat. There is a Goldilocks zone for the lubricant viscosity and it is different for different engines.
Here is a video about it:
Here is a video about it:
Think bout it; wouldn’t it hold heat longer than thin oil like 0w16 or 0w20? Just guessing
should be easy enough to check. heat up similar volumes and track the temperature as they cool down. the denser oil should cool down slower, but that might not be the highest kv100 oil.....
On my VW's that are air cooled I run 20-50 in my air cooled van. I believe the extra viscosity allows the oil to flow slower through the oil cooler so more heat gets taken out. May just be my guess but on the heat of the dipstick test, the thicker oil is cooler on my fingers.
No.
There's a property of materials called "specific heat" which just tells you how much energy it takes to raise the temperature of a fixed mass of the material by an increment of temperature. Typically the units of specific heat are energy-mass °Temp. For example, the specific heat of water is 4.18kJ/(kg-°C). Meaning, it you want to raise the temperature of kg of water (1 liter by volume) by 1°C. it takes 4.18kJ of energy to do so.
Oil, at 100C, has a specific heat of only about 2.2-2.5, depending on temperature and blend. It's just over half as heat-dense as water. This is why water cooling (with glycols) is so much more effective than oil cooling in terms of heat transport.
Now, if the only difference between two oils is density, then the higher density oil will store more heat on a volumetric basis; it has more mass for the same volume. On the high end, engine oils will be in the 0.9 range for density with less dense oils in the 0.83 range. It's not a huge range overall, but enough to matter perhaps in some conditions.
There's not much to the thermodynamic differences of oils as a function of viscosity. Your oil pump is positive displacement so the flow to the oiling points of the engine isn't reduced enough to matter (imo) with thicker oil until the oil pump goes into bypass. While thicker oil makes it harder to force oil through tight bearing clearances and such, it also makes your oil pump more efficient by lowering its internal leakage. So net/net, very similar flows result. You'll just have higher oil pressure and use more pump shaft work with the thicker oil to do the same flow work.
The higher densities of some oils might be entirely offset by lower specific heats of different base stocks or base stock blends.
A thicker oil will not cause an otherwise healthy engine to overheat, nor is going to a thinner oil going to magically correct your hot-runner and make it run closer to the desired temperature range.
As a general rule, lower flow rate through a heat exchanger will cause less heat, not more heat, to be rejected.
Here's why:
A lower flow rate isn't just a lower fluid flow rate, but it's also a lower energy flow rate if its the same oil at the same temperature. Your sending less total heat (per unit time) to the heat exchanger. You cannot get more heat out of the exchanger if you are sending less to it.
You are not lowering the operating temperature of an air-cooled engine by using thicker oil. Don't get me wrong, I think 20w50 is appropriate for your application, it's just not causing the engine to run cooler than, say, a 15w40 would.
How are you measuring temperature and where is the probe located?
Remember, it's not real unless it repeats.
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Is this similar to "Do you get wetter walking, or running through the rain"?
answer is running per mythbusters episode I saw years ago. You want to not get as wet? walking apparently is the answer....though I'm sure there's rain volumes that render this finding moot.
Extra heat is “extra” and will obviously take longer.
Obd II PID. I believe the temperature is measured by the CVVT system.
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Yes too many variables to answer absolutely. Wind direction, vs travel direction is an easy choice as an example.
But basically 6, or half dozen sounds good.
Not really. This is far more clear cut.
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