Coolant Temp. VS Oil Temp ???
 

How does oil temperature vary with coolant temperature with NON spirited driving? How does ambient temperature affect oil temperature under the same conditions.

I live in a warm summertime climate, and wanted to see if going from 5W40 to 5W50 would reduce engine wear under higher ambient conditions.

My coolant temperature stays the same no matter what the ambient temperature.

I hope to not devolve into an oil discussion.

John

While I don't have any data, my hypotheses would be the coolant temperature reaches its maximum faster than oil does. There is a point where the oil temp exceeds the coolant temp (again depending on driving conditions). The oil temperatures are above 190. I doubt ambient temperature will have any effect on oil temperature at those operating temps. I did switch to 5W50 several years ago and have had no issues.

Live in SE Fl and have been usung 5w-50 for many years and seems to be fine! As far as an algorithm of oil vs coolant temp not sure where you would find one.
It is fact oil temp lags coolant temp during warm up, hence the reason one should wait till oil temp reaches its run temp before driving hard! In these cars I go by when the oil level will register, which means oil should be up to temp.

If there was any wear from running the 5w-40 oil you would know it by how the engine runs, its oil consumption.

These cars are factory tested under some of the highest ambient temperature conditions around -- USA southwest desert and South Africa -- and many privately owned experience far higher summer time temperatures than where you live and drive and are just fine with the factory fill oil of 0w-40.

However, if winter temperatures are mild enough that you do not need to run 0w-40 oil in the winter then you can if you want switch to 5w-50 oil. Last time I checked the approved oils list Mobil 5w-50 was the only approved 5w-50 oil.

(I've run this oil in both of my cars, 2002 Boxster, 2003 996 Turbo) now for a few years year 'round. The Boxster engine has over 313K miles while the Turbo engine has over 156K miles. Might point out the bulk of those miles were with 0w-40 oil in the engine. I know you didn't want an "oil thread" but I feel obligated to point out that at least in my experience 0w-40 oil appears to be quite up to the task of providing an engine, both a N/A and a turbo-charged engine, satisfactory lubrication under a variety of operating conditions and over hundreds of thousands of miles.)

Generally oil temperature lags coolant temperature as the engine warms up then oil temperature generally leads coolant temperature from this point on.

Spent some time in a Porsche Cayenne (diesel) loaner that had an oil temperature read out and it was rather surprising how much variation there was in oil temperature and how the temperature shot up under increased engine load.

OTOH, not so suprising when one considers the oil is in some ways in contact with hottest parts of the engine and its elevated temperature and temperature variability reflects this. Oil is a bit slower to give up its heat too than coolant.

There is the path heat must take to leave the oil. Oil gives up its heat to the coolant (to be sure some oil heat is given up to the cooler metal surfaces the oil comes in contact with) which is not much cooler than the oil while coolant gives up its heat to air which is probably 100F cooler than the coolant.

Rob (993GT) did a cold start to full warm analysis a couple of years ago. If I am remember correctly oil temp lagged behind coolant temp by a couple of minutes. I remember thinking then the lag time was less than I would have thought.

Thanks for the information so far. I did a little research online and found this on "Bob is The Oil Guy". I found the read interesting.

https://bobistheoilguy.com/forums/ub...pics/2949632/1

BTW, I will use Mobil 1 5W50 on next fill.

NAPA has a special right now for $5.95/QT On Line.

John

I usually wait till the oil pressure drops down to 2 bar, indicates well that the engine is fully warmed up. I'm pretty sure I've been able to register oil level and the engine wasn't fully warmed up based on the fact that when I put the car in N, the oil pressure was around 2.5 bar.

Read thru some of the posts, saw the comment on the temp difference in the Corvette, keep in mind the corvette may not have had an oil cooler like in the turbo. One would think oil temp and coolant temp in the turbo should be close.

I've monitored and logged oil temps with my Access Port and it's fully warmed up after 5 min. or so on the freeway, so my observations mirror Rob's.