Ideal Oil Temperature

[Clevy]

Originally Posted By: HosteenJorje
Is 176F hot enough to boil off the condensation in crankcase oil that builds up due to city driving? I think most vehicles have 180/190 thermostats. Is that hot enough to produce oil temperatures sufficient to boil of contaminants?.



Of course.

Water will evaporate whether it's 1c or boiling,the difference is the speed of evaporation.
So yes. Condensation will boil out whether the oil is 160f or 212f.

 

[SHOZ]

They obviously won't boil off water as that boils at 212F but it will be sufficient to drive off the lighter hydrocarbons and water from blowby. The longer it is at that temp the better it is.

 

[Shannow]

Originally Posted By: bullwinkle
Vinu-was that OEM paper recent (with synthetic oil), or older (with conventional)? Would believe even a syn blend could handle higher than 80C easily?


The doubling per 10C is an industry rule of thumb, and not indicative of the temperature that oil can tolerate...the synthetic blends will have a longer baseline, but still approximately the rule of thumb.

The 80C is just a point that's chosen as a moderate service baseline. At 50C, there's still degradation in service, but it's 2x2x2=8 times slower for want of a better measure....could have a 50C baseline and say 100 is 32 times worse, but nearly nothing operates at 50C, as you need 80ish to get everything functioning (viscosity, moisture removal, additives if heat activated), and it's a fairly typical design point.

 

[HKPolice]

Originally Posted By: vinu_neuro
According to one of the big Japanese OEMs, idea oil temperature is 80C/176F. I don't remember how much it was, but in another paper oxidation was described to go up some % for every 10C beyond 80. As of 2003, this OEM was able to estimate oil temperature -6.6 to +3.6% without having an oil temperature measurement, for their oil life monitoring system.

You can see why oil analysis by Blackstone is so lacking. TAN and Oxidation, and to a lesser extent nitration and sulfation are also extremely important.

The full PDF is here: http://hondakarma.com/attachments/engine-oil-deterioration-monitoring-system-pdf.12590/

It's a paper from Honda from 2003, good read.

 

[SteveSRT8]

Originally Posted By: SHOZ
They obviously won't boil off water as that boils at 212F but it will be sufficient to drive off the lighter hydrocarbons and water from blowby. The longer it is at that temp the better it is.


You hit it right on the head.

It's just as important to know the DURATION at the temp as the temp itself. Huge factor in most oil life algorithms used in vehicles OLM's...