Coolan/Oil Temperature

Messages
137
Location
los angeles
On average, what's the difference in degrees Fahrenheit between coolant temperature and oil temperature when they are at operating temp?
 
Messages
742
Location
Lake Anna, VA
In my 2000 Jeep Wrangler with the 2.5L I4 my coolant gauge shows 195-200 degrees depending upon load while the oil temp stays around 180 degrees depending upon load. Under aggressive driving my oil temp has gone to 195 degrees and coolant to 210 deg.
 
Messages
39,805
Location
Pottstown, PA
Ryan ..how 'bout a detail on your oil system. First off ..where in the heck do you hang a gauge in a TJ that isn't either out of the way for looking at it ...or hitting your knee or temple ..or ??? This has bugged the heck out of me since I got the thing. I want to put both a trans temp and an oil temp ..but underneith the center pod seems a bit too remote. Pillar mounts don't look promising either ..and I'm not sure if I want to mount something on that little launching platform that is located right abouve the center vents. I've installed the MOPAR coolant/oil exchanger/cooler (filter spacer). It runs inline with the heater. This, I think, will sort of index the oil at around 205 without too much deviation from that.
 
Messages
40,743
Location
Great Lakes
My coolant temps stay near 195F, +/- a few all year long. My oil temps. run around 175-180F during cold winter days. During summer they're usually closer to 190F. Car: '01 Audi A4, 1.8T
 
Messages
2,933
Location
Georgia/Retired
My only vehicle that has a oil temperature sensor is my 1997 Passat. The water temperature runs at 190ºF and the oil normally runs between 205ºF and 220ºF.
 
Messages
336
Location
White House, TN USA
quote:
Originally posted by Blue636:
quote:
Originally posted by Tree Hugger: With the exception of the Passat above all the oil temps seem to be below the coolant temps. So what is the 'summer weight oil' justification again?
Probably to maintain viscosity.

At the same temperature? With all politeness, I suggest you think again.
 
Messages
742
Location
Lake Anna, VA
Gary Allan....I mounted my Autometer 2 1/16 Oil Temp gauge on the center of my dash right above my Part time 4wd shifter handle. It was about the only place I could find that was out of the way and not really noticeable. I also angled the mount so all I have to do is glance down and I can see it perfectly. I am running a single remote oil filter system and I use a Wix 51773 extended filter. It's mounted to the firewall right below where the factory airbox was. I used a T block and located the sending unit for the temp gauge there also. This setup increases oil capacity for my 4 banger from 4 qts stock to 5 1/4 now.
 
Messages
3,593
Location
Outside smalltown, IL
quote:
Originally posted by Tree Hugger:
quote:
Originally posted by Blue636:
quote:
Originally posted by Tree Hugger: With the exception of the Passat above all the oil temps seem to be below the coolant temps. So what is the 'summer weight oil' justification again?
Probably to maintain viscosity.

At the same temperature? With all politeness, I suggest you think again.

This has been my question for quite a while now. I've never seen it answered...
 
Messages
250
Location
Phoenix, AZ USA
My experience is that in a car without an oil cooler (except the oilpan, of course), and except in cool/cold weather, the oil temp will run around the same or usually higher than the coolant temp. IOW, in summer, coolant will run 190 - 200dF. while oil will be running 200 - 250dF. Of course, the last 44 years of my experience has been in the desert. My Cayenne Turbo has an oil-temp gage and apparently-very-good oil/water heat exhanger, and I've never seen its oil temp above 200dF. while I have seen its coolant temp pushing 230dF. on the racetrack.
 
Messages
2,053
Location
Sequim, WA
Blue636 asks: On average, what's the difference in degrees Fahrenheit between coolant temperature and oil temperature when they are at operating temp? That's a very hard question to answer. It will be very dependent on the design of the engine. As a very general observation based on vehicles that I have owned with oil temperature gauges and observations of others, the oil temp runs 10-20 degrees F above the coolant temperature in the summer and 10-20 degress F below coolant temp in the winter. That spread will increase with factors such as track time or very cold temperatures. My WRX for example, which has a water-oil cooler/heater runs an oil temperature of ~160F pulling the 5 mile grade to my house in the winter. In the summer the oil will reach 190F on that same grade. The car has a 172F thermostat. If your oil temperature did in fact run the same winter and summer there would be no need to change grades. That is rarely, if ever the case. Given the oil temps I see with my WRX, I would need to run a 20 weight in the winter and a 40 weight in the summer to maintain the same viscosity to the engine. I run a top quality synthetic XW-30 weight throughout the year. Ed
 
Messages
273
Location
High Up in the Rockies
Audi, 2003 Bi-Turbo, 6-spd man. trans. At stable coolant operating temperatures, the oil temnp gauge sits at ~215 degrees F. It usually stays there until I step into the turbos. I goes as high as 250F on loooong uphill mtn. grades but comes down fairly quickly after backing off the throttle. I do not know what the stock coolant thermostat is in this car for comparison. DEWFPO
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by Tree Hugger: Thank you, at last one hard data point!
1996 Corvete LT-4 that I have had since last November. Driving under various conditions in Northern California, oil temperature runs 10 to 15F higher than the coolant temp once t6hings have stabilized. The car does not have an oil cooler. Coolant runs in the 195 to 205F range once warmed up. I have had oil temp gauges on other cars and trucks without oil coolers. Oil on my vehicles has run a bit warmer than the coolant for normal driving to quite a bit hotter for hard driving.
 
Messages
107
Location
Richmond, Va
It has a lot to do with where the temperature sensors are, but in my experience with aftermarket gauges used in many cars, is that the oil temp generally is 20degF higher than the coolant. It would have to be, to ensure that there is rapid elimination of water absorbed into the crankcase by ambient air infiltration, the blowby of the products of combustion, or condensation during warmup on the cylinder walls. That is one reason why I do not recommend low temp thermostats for daily drivers.
 

Blue636

Thread starter
Messages
137
Location
los angeles
quote:
Originally posted by Tree Hugger: With the exception of the Passat above all the oil temps seem to be below the coolant temps. So what is the 'summer weight oil' justification again?
Probably to maintain viscosity.
 

Blue636

Thread starter
Messages
137
Location
los angeles
quote:
Originally posted by Tree Hugger:
quote:
Originally posted by Blue636:
quote:
Originally posted by Tree Hugger: With the exception of the Passat above all the oil temps seem to be below the coolant temps. So what is the 'summer weight oil' justification again?
Probably to maintain viscosity.

At the same temperature? With all politeness, I suggest you think again.

Well, there it is. The last half of these posts show that oil temperatures can exceed the coolant temps, and I'm not surprised. I think the oil has a much larger capacity for heat than any coolant solution and would naturally get hotter, especially in 90 degree weather with stop and go traffic.
 
Messages
345
Location
Northern California
In a stable temperature situation with the oil temp measured in the oil pan I should see an average temperature maybe 200 or so degrees. How can I compare that to the temperature coming off a turbocharger bearing? That oil is trying to cool a bearing that could be over 1000 degrees at times. I don't know but I would assume the oil could be well over the average oil temperature. Further I wonder if the bearing temperature changes much between summer and winter considering the water/coolant thermostat is designed to keep the engine temperature constant or as close to possible to constant, assumeing an adequate cooling system. Burn temperatures in a cylinder probably change more by mixture changes then outside temperature. After this how I should I compare the oil going to the rest of the engine? Main bearings? Cam lobes? It soon gets to complicated for me.
 
Messages
336
Location
White House, TN USA
quote:
Originally posted by Blue636:
quote:
Originally posted by Tree Hugger:
quote:
Originally posted by Blue636:
quote:
Originally posted by Tree Hugger: With the exception of the Passat above all the oil temps seem to be below the coolant temps. So what is the 'summer weight oil' justification again?
Probably to maintain viscosity.

At the same temperature? With all politeness, I suggest you think again.

Well, there it is. The last half of these posts show that oil temperatures can exceed the coolant temps, and I'm not surprised. I think the oil has a much larger capacity for heat than any coolant solution and would naturally get hotter, especially in 90 degree weather with stop and go traffic.

Well, there it isn't, actually. [Roll Eyes] We only have ONE hard data point that shows the oil running hotter in summer than winter. I wish the others had been specific that it DIDN'T vary summer to winter, but they certainly didn't mention it. The fact that the oil can exceed the coolant temperature says NOTHING about summer versus winter oil temperatures.... I'm still very dubious (and no, your 'judgement' that it ought to be hotter in summer than in winter doesn't convince me). [I dont know]
 
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