What is considered as 'Optimal' engine oil temperature... ?
- Thread starter Free Ride
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Running on the highway, which is light duty and really the only place to get consistent temperature readouts, I prefer to see 80-90 degrees C. Increase the load and oil temperature goes up a bit, increase rpm and oil temperature goes up a lot.
More important is that the 80°C can be maintained in winter aswell. Note that with 80°C bulk temperature, the oil will be significantly hotter in the piston area and when draining to the sump, more than enough to evaporate all water.
Also note that oil degradation rate doubles for every 10°C rise.
More important is that the 80°C can be maintained in winter aswell. Note that with 80°C bulk temperature, the oil will be significantly hotter in the piston area and when draining to the sump, more than enough to evaporate all water.
Also note that oil degradation rate doubles for every 10°C rise.
238° F = ~114° C.
212°-220° F = 100°-104.4° C.
200°-225° F = 93.3°-107.2° C.
270° F = 132.2° C.
194° F = 90° C.
235° F = 112.7° C.
In my different VAG cars it is not a dummy number !
The engine oil temperature is measured carefully and changes often and quickly between the individual degrees.
So it is not a dummy signal or a filtered signal.
( I have also verified this with VCDS diagnostics while driving )
244° F = ~118° C.
195° F = ~90.5° C.
200° F = 93.3° C.
OK.
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I am referring to the coolant temp (194) not oil w/r to dummy gauge and I can assure you it's a dummy gauge based on logging. Yes oil displayed is real.
Why even bring up the coolant temperature in the thread ?
Why write about things that have nothing to do with the question in the thread ?
It'll vary quite a bit between different engines, uses, and oils. A fellow racer drives his twin turbo Mustang all over the country. A few times a year, he drives it 1000+ miles, runs mid-8s 1/4 mile all week, and then 1000+ miles home. Cruising at 70-75 mph and 2200-2500 rpm, his sump temp is ~260°F in the summer with HPL BAS 10W-50.
The doubled rate of degradation every 10°C statement isn't entirely true for engine oils. The exposure to blow-by gases, fuel and water dilution, and ambient air conditions skew that significantly. Burning 1 gallon of gasoline produces 1.033 gallons of water. (C8H18 + O2 = CO2 + H2O) That water is going somewhere. Just because water is a vapor doesn't mean it won't enter the crankcase and condense in the cooler sump, especially after the engine has been shut off. Hence, I like full operating temp to be above water's boiling point (212°F) and the 50% distillation point of pump gasoline (195-210°F).
The doubled rate of degradation every 10°C statement isn't entirely true for engine oils. The exposure to blow-by gases, fuel and water dilution, and ambient air conditions skew that significantly. Burning 1 gallon of gasoline produces 1.033 gallons of water. (C8H18 + O2 = CO2 + H2O) That water is going somewhere. Just because water is a vapor doesn't mean it won't enter the crankcase and condense in the cooler sump, especially after the engine has been shut off. Hence, I like full operating temp to be above water's boiling point (212°F) and the 50% distillation point of pump gasoline (195-210°F).
I don't think it's really anything to worry about, unless you do a lot of short trip Winter driving. Then you almost never get the oil hot enough to get rid of moisture contamination. If the trips are really short, it can even add to it.
That's when you get that light tan, creamy Mayonnaise on the inside of your oil filler cap, that's conducive with oil and moisture mixing in the engine. Oil does not have to be above 212 F to get rid of moisture. But it helps to accelerate the process if it is.
Patman
Staff member
That’s a good point. Water can still evaporate at room temperature but it’s just going to take longer. When I take my Corvette out for a drive on a cold winter day the oil temperature is generally in the 80-90C range. So I make sure I drive it for about an hour and that way I can be more confident that by the time I shut it down there is no water left in the oil.
Yes the thermostat is electric, water pump I think is standard type. Was quite impressed how the oil temps drop in hot outside temps while loading the engine up.
My Gen Coupe 2L turbo will run at 10F over coolant temp (180-185F) usually after fully warmed up. The other day at 97F and on the interstate it got up to 210F. On the track I usually could not finish the last lap in the session due to oil temps exceeding 300F. In the winter it struggles to get above 160F.
Always wonder what my Accent oil temp was as with OE 180F thermostat it's really a cold blooded iron block engine. And with the manual trans it will lose temp when decelerating in gear. So around town it's always below the tstat opening point.
Always wonder what my Accent oil temp was as with OE 180F thermostat it's really a cold blooded iron block engine. And with the manual trans it will lose temp when decelerating in gear. So around town it's always below the tstat opening point.
That was in response to this post which I quoted...Why even bring up the coolant temperature in the thread ?
Why write about things that have nothing to do with the question in the thread ?
My oil temp never exceeds the coolant temp?
What's "optimal" has a lot of parts to it. Max fuel economy and least emissions will have it's optimal range. Max engine longevity will have another.
I feel happy if my vehicle's bulk fluid temperatures stay between 180-199F once up to temp. My BITOG PTSD kicks in at over 200F.
I feel happy if my vehicle's bulk fluid temperatures stay between 180-199F once up to temp. My BITOG PTSD kicks in at over 200F.
That would be the exception. Do you have an oil cooler? Without an oil cooler, oil sump temp usually tracks 10-30°F above coolant temp.
I like the way it was explained here.
260° F = 126.6° C.
212° F = 100° C.
OK.
OK.
198° F = 92.2° C.
210° F = 98.9° C. ( summer )
300° F = 148.9° C. ( track )
160° F = 71° C. ( winter )
We can all do the math between degrees C and degrees F. Why do you keep posting that?
The oil cooler thermostats on several of my cars open at 85C. Clearly, that’s the point at which those manufacturers think the oil should start being cooled.
At 85-90C, the oil is warm enough to drive off moisture and flow well, but not so hot as to thin out, particularly in the turbos.
The oil cooler thermostats on several of my cars open at 85C. Clearly, that’s the point at which those manufacturers think the oil should start being cooled.
At 85-90C, the oil is warm enough to drive off moisture and flow well, but not so hot as to thin out, particularly in the turbos.
Here's a temp log showing oil/coolant/trans temps over a ~20 min track session in ~90 deg temps in my Sportwagen if anyone is interested.
datazap.me
datazap.me | Karstgeo72 | VIR temp log
datazap.me
Yes, very strange.
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