Fluid temps when it's cold out

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OVERKILL

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I think we had a discussion on this in the past as one of the key points of discussion regarding winter driving has been oil temperature versus coolant temperature. I have indicated that this depends on the presence, or lack thereof, of an oil/coolant heat exchanger, which many vehicles, particularly with the pursuit of thinner lubricants, have been fitted with. My last four vehicles have all had this feature and subsequently coolant and oil temperatures track well together during warm-up.

Today it was -20C (-4F) which is a bit warmer than previous days, but unfortunately I didn't think about this until today. I can check at colder temps if there is interest.

I figured I'd snap a few shots of the VIC in UConnect for the Jeep after approximately 10 minutes of driving, here are the results:





As can be seen oil/coolant track basically identically. Trans temperature lags significantly in comparison. Also, intake air temperature is an interesting one. It drops considerably when moving however between the time I stopped and the time I took the pictures it had increased to what you see from several degrees cooler. She breathes near the rad, which is likely an important part of that.
 
Oil temp in wife's Q5 is at around 175F when driving around town when it's cold like today (around 10F).

BTW, these nice digital gauges make me want to get an SRT.
smile.gif
 
Originally Posted By: Alex_V
Must have a pretty good oil cooler. Hopefully it keeps the two temps that close when you're thrashing it on a hot summer day.
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Yeah, it's a pretty good sized exchanger and does a good job year-round.

Here's the parts diagram for it:
oil_cooler_6.4L_01.jpg
 
My 135i still hits the standard 240-ish F oil temperatures when below freezing.

Ive never found any vehicle that doesn't track to normal operating temperature in below freezing temperatures. Diesels can be tough to get to temp without load, and older small 4 cyl engines would also take forever. Modern small engines come up to temp well, I can't imagine a behemoth having an issue.
 
Originally Posted By: JHZR2
My 135i still hits the standard 240-ish F oil temperatures when below freezing.

Ive never found any vehicle that doesn't track to normal operating temperature in below freezing temperatures. Diesels can be tough to get to temp without load, and older small 4 cyl engines would also take forever. Modern small engines come up to temp well, I can't imagine a behemoth having an issue.


My M5 was cold blooded on the oil side of things, because of its big cooler in the valley. I believe I posted some pics of it in the past. It really could not get the oil up to temp in winter months.
 
Cool info! Was that slow city driving or highway driving? How much oil does the Jeep hold? Any info on where the temp probe for the oil takes the measurement?

I installed a transmission temp sensor and see similar lag compared to coolant temp. Considering an oil pressure and oil temp sensors next. My IR thermometer on bottom of sump pan shows 150 F after 10 minutes of city driving in 10 F ambient temp. Coolant temp was stable at 185 F by then. Not sure how accurately the thermometer reads or how well pan temp reflects actual oil temp.

Both transmission and engine have oil to coolant heat exchangers in the radiator end tanks.
 
Originally Posted By: OVERKILL
As can be seen oil/coolant track basically identically.

As I've mentioned before, with the G37 at least, even ten minutes of driving in these temperatures, and you won't touch the oil filter with your bare hands. It's a totally different experience from the Chevy small blocks of the day, when I could change oil in summer after a day's running in 30 C or warmer, without gloves.
 
Originally Posted By: VeryNoisyPoet
Cool info! Was that slow city driving or highway driving? How much oil does the Jeep hold? Any info on where the temp probe for the oil takes the measurement?

I installed a transmission temp sensor and see similar lag compared to coolant temp. Considering an oil pressure and oil temp sensors next. My IR thermometer on bottom of sump pan shows 150 F after 10 minutes of city driving in 10 F ambient temp. Coolant temp was stable at 185 F by then. Not sure how accurately the thermometer reads or how well pan temp reflects actual oil temp.

Both transmission and engine have oil to coolant heat exchangers in the radiator end tanks.


This was all city driving, was dropping off the kids for New Years at a sitter.

The Jeep holds 7L of oil roughly. The temp sensor is on the front of the engine, just below the left cylinder head IIRC.
 
Originally Posted By: OVERKILL
Originally Posted By: JHZR2
My 135i still hits the standard 240-ish F oil temperatures when below freezing.

Ive never found any vehicle that doesn't track to normal operating temperature in below freezing temperatures. Diesels can be tough to get to temp without load, and older small 4 cyl engines would also take forever. Modern small engines come up to temp well, I can't imagine a behemoth having an issue.


My M5 was cold blooded on the oil side of things, because of its big cooler in the valley. I believe I posted some pics of it in the past. It really could not get the oil up to temp in winter months.


The 135i cooler is relatively undersized, resulting in high temps.

I'm sort of surprised any of these aren't thermally controlled. Even my early 80s diesels have thermostats to prevent the oil from being too cold.
 
Originally Posted By: Garak
Originally Posted By: OVERKILL
As can be seen oil/coolant track basically identically.

As I've mentioned before, with the G37 at least, even ten minutes of driving in these temperatures, and you won't touch the oil filter with your bare hands. It's a totally different experience from the Chevy small blocks of the day, when I could change oil in summer after a day's running in 30 C or warmer, without gloves.


I dunno. I noticed this when servicing 20kw kubota IDI diesel gensets after the hurricanes. And they had 7qt sumps.
 
Originally Posted By: JHZR2
Originally Posted By: OVERKILL
Originally Posted By: JHZR2
My 135i still hits the standard 240-ish F oil temperatures when below freezing.

Ive never found any vehicle that doesn't track to normal operating temperature in below freezing temperatures. Diesels can be tough to get to temp without load, and older small 4 cyl engines would also take forever. Modern small engines come up to temp well, I can't imagine a behemoth having an issue.


My M5 was cold blooded on the oil side of things, because of its big cooler in the valley. I believe I posted some pics of it in the past. It really could not get the oil up to temp in winter months.


The 135i cooler is relatively undersized, resulting in high temps.

I'm sort of surprised any of these aren't thermally controlled. Even my early 80s diesels have thermostats to prevent the oil from being too cold.


The M5 had a thermostat on its oil cooler circuit, but IIRC, the cooler was air/oil and even when bypassed, there was enough heat shedding going on that it was just not a good winter setup. In comparison, all the Chargers and the Expedition have been oil/coolant which heat up the oil in tick with the coolant.
 
The oil temp in my Ram comes up quick to about the same as the coolant even in the really cold days we have had lately. The heater in my Ram works really good as well, thankfully lol
 
My S65 M3 runs around 215F in 90 ambient and around 205 in single digits with its huge cooler. My BRZ similar with no cooler. This is after 25 minutes averaging 3500-4000RPM and a couple redline pulls. On the track it’s a drastically different story.
 
Originally Posted By: JHZR2
I dunno. I noticed this when servicing 20kw kubota IDI diesel gensets after the hurricanes. And they had 7qt sumps.

Yes, very vehicle specific. The G37, I can't touch the filter after even 10 minutes. The cabs were never a problem, even on a hot day. The Audi wasn't half bad; it always had relatively low oil temperatures.
 
I don’t have any temperature data but I can tell the oil in my truck stays cooler in cold temps by oil pressure. When it’s hot outside my idle oil pressure is 20 psi and my off idle pressure is about 42 psi. When the temps are cold they are 50 psi idle and off idle pressure is the same. When it warms up it idles around 30 psi even after a 60 mile highway cruise. No oil cooler on that engine.
 
Originally Posted By: tig1
This is most Cool! OH! I mean Neat since it's wicked cold outside. Is this an add on of OEM?


OEM.
 
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