Mazda CX-50 2.5S Winter Time Road Trip Engine Oil Temp Observations

[KrisZ]

Hmm. I'd like to watch a dog dish full of water on a 33 degree day to see how fast it evaporates vs. boiling. That's assuming no wind and no dog.

Just how much water do you think it’s in your oil?
In a normally operated engine, that sees trips of roughly 30 minutes or longer, any moisture present from the cold start will be long gone before the oil hits this magical 212f temp.

I seriously don’t understand why it’s such a big deal.

 

[edyvw]

And it’s those hot spots, like bearing journals, camshaft lobes etc. is where hight temperature, and high sheer happens which activates the needed additives. Also, different additives have different operational temperature ranges and oils are blended with many different additives. 212f is not some magical number that needs to be achieved.

As far as hitting 270f-300f, it’s fine for short periods of time, but that is not good for sustained operation. Oil loses viscosity with temperature so you’re affecting your HTHS and MOFT. Also the oxidation rates skyrocket at those temps.

There is a reason why most engines run below 212f in normal operation and that’s because it keeps the above parameters in check and leaves lots of headroom for high load operation where the oil temps will inevitably climb a lot higher than normal, without the need for large coolers and thermostatic temp control.

Which most engines run below 212 oil temperature?
We are not talking about 190f. I yet to see engine that runs this cold. Toyota runs oil temperature in 220-230f range, with “local hotspots.”
You don’t need large coolers run 220f oil temperature. You need balanced cooling system. My Sienna ran 230f on hwy, and 2GR-FE is considered “cold engine. My BMW ran 230f on HWY without any cooler, radiator or fluid/fluid exchangers.
This is temperature in East coast. I am about to drive to area where it is -25f this morning, and guess what? They sell Mazda here too.
This is addressing another issue through low temperature by manufacturer.

 

[KrisZ]

OK, I shouldn’t have said most, my bad. But since oil temp monitoring is not exactly standard, I would say it’s hard to estimate one way or another.

For example, my minivan runs 180f-190f all the time. OPs Mazda apparently runs pretty cool oil temps too.

So it’s hard to say just how many.

Edit:
Here is my Toyota CHR at roughly 100f ambient and a 40 minute commute

 

[CBR.worm]

That's interesting. My two Nissans, a V6 and V8, keep the oil at least as hot as the coolant once it is up to temp. The oil temp will rise under extreme duress, but it generally stays between 95c and 105c while moving, regardless of ambient temp. If it is really cold out, it might drop to 85C idling - which would match the coolant temp.

Mazda must know what they are doing, they've been successful for a long time. I always like to see different approaches to things.

 

[edyvw]

OK, I shouldn’t have said most, my bad. But since oil temp monitoring is not exactly standard, I would say it’s hard to estimate one way or another.

For example, my minivan runs 180f-190f all the time. OPs Mazda apparently runs pretty cool oil temps too.

So it’s hard to say just how many.

Edit:
Here is my Toyota CHR at roughly 100f ambient and a 40 minute commute

View attachment 257873

So your engine temperature is 200f. That is way above his temperature.
Also, take into consideration that he was on hwy. That means that in the city, short drives, that oil has serious nitration issues. Most engines reach 140-150f in city, and that is considered low.
IMO, this is engineering trick to address bigger issues.

 

[edyvw]

That's interesting. My two Nissans, a V6 and V8, keep the oil at least as hot as the coolant once it is up to temp. The oil temp will rise under extreme duress, but it generally stays between 95c and 105c while moving, regardless of ambient temp. If it is really cold out, it might drop to 85C idling - which would match the coolant temp.

Mazda must know what they are doing, they've been successful for a long time. I always like to see different approaches to things.

IMO they do know what they doing. They are keeping oil temperature low to prevent something else that could be costly during warranty.
That oil in short trips is running way below that. All manufacturers are trying to boost oil temperatures at hwy to improve efficiency. More heat, more performance and better mpg.
Take into consideration that majority people use these Mazda’s to go to work, grocery getters, not road trip warriors.

 

[OneLonelyBurrito]

Observations from my commute today. Ambient temperature was low to mid 20s. My commute is about 56 miles one way, or about 1 hour depending on traffic. While driving to the office, my oil temperature maxed out at ~172F but typically stayed ~168F, but the air shutter flaps never opened limiting air flow into the engine bay. On my way home, while driving on the highway, it stayed about 168-170F with the shutter flaps shut the entire way. Once I got into the slower roads closer to home, the oil temp actually started to creep up and finished at 176F. So it appears the convective heat transfer from highway speeds plays a big role in oil temp since it creeps up in slower moving situations and when the air shutter flaps are closed it maintains a slightly higher oil temp than when they are cracked open.

 

[KrisZ]

So your engine temperature is 200f. That is way above his temperature.
Also, take into consideration that he was on hwy. That means that in the city, short drives, that oil has serious nitration issues. Most engines reach 140-150f in city, and that is considered low.
IMO, this is engineering trick to address bigger issues.

I think you missed that the ambient in my case was around 100f.
Ambient temp has a big effect on the oil temps in cars that don’t have thermostatically controlled oil coolers.

 

[edyvw]

I think you missed that the ambient in my case was around 100f.
Ambient temp plays has a big effect on the oil temps in cars that don’t have thermostatically controlled oil coolers.

No it doesn’t. If cooling system is properly executed, it will always keep it in the sweet spot, +-5 degrees. I didn’t miss your ambient temperature.
I spend a lot of time in summer in Las Vegas and my cars run same on OBD. Warm up time is different story.
Another thing with such low oil temperature, I wonder how intake valves look like on that engine considering it is DI.
Also, take into consideration that racing oil cooler thermostats open at around 180f. There are numerous reasons why not to cool oil below that. My oil cooler thermostat on BMW opens completely at 230f.
This is cheap solution to engineering problem.
Another option is that this is some kind of hot climate optioned car. Highly doubt, but whatever.

 

[KrisZ]

No it doesn’t. If cooling system is properly executed, it will always keep it in the sweet spot, +-5 degrees. I didn’t miss your ambient temperature.
I spend a lot of time in summer in Las Vegas and my cars run same on OBD. Warm up time is different story.
Another thing with such low oil temperature, I wonder how intake valves look like on that engine considering it is DI.

Well yes, on very long trips it will eventually equalize to a similar temps. But that’s the thing with cold outside temps, those last 10-20f takes a long time.

On a work commute, like mine that’s about 40 minutes long, I do see a difference at the end of the trip, which can be 20f or more.

 

[edyvw]

Well yes, on very long trips it will eventually equalize to a similar temps. But that’s the thing with cold outside temps, those last 10-20f takes a long time.

On a work commute, like mine that’s about 40 minutes long, I do see a difference at the end of the trip, which can be 20f or more.

Depends on how cooling system is designed. This low temperature is by design to mitigate something else. Your commute is not average commute which is far shorter. I have never, ever seen oil temperature lower than 180f here, including as low as -42f, and that was X5 diesel, and diesels tend to go low.

 

[OneLonelyBurrito]

Depends on how cooling system is designed. This low temperature is by design to mitigate something else. Your commute is not average commute which is far shorter. I have never, ever seen oil temperature lower than 180f here, including as low as -42f, and that was X5 diesel, and diesels tend to go low.

It could also be that there isn't enough engineering justification to add measures to increase oil temperature on this engine. Like if its not gonna do any damage, why add another leak point and additional cost of a heat exchanger for the engine oil. They have one for the transmission oil, so controlling oil temps in the transmission was important enough to add a oil to coolant heat exchanger.

 

[Nesterenko]

Bottom line is oil temps are low. Higher temps within reason are probably beneficial to oil life and of course CAFE. I myself would look into this further with Mazda and get an explanation.

 

[edyvw]

It could also be that there isn't enough engineering justification to add measures to increase oil temperature on this engine. Like if its not gonna do any damage, why add another leak point and additional cost of a heat exchanger for the engine oil. They have one for the transmission oil, so controlling oil temps in the transmission was important enough to add a oil to coolant heat exchanger.

I do think that they did something to mitigate another issue. The problem is flow, nitration, emulsion (on long trip that is not an issue), overall temperature of an engine which can induce intake deposits. That is before the fact that additives in oil need certain temperature to properly work.
The fact that coolant thermostat is only 180f instead more common 195f is also indicative of attempt to keep it low.
Like I said, BMW did that trick on N63 to cool off engine bcs. it was hot V design. They had issues with valve stems, turbo lines etc. But even than, they kept it at 195f.

 

[edyvw]

Bottom line is oil temps are low. Higher temps within reason are probably beneficial to oil life and of course CAFE. I myself would look into this further with Mazda and get an explanation.

Yeah, I would definitely check things out.

 

[OneLonelyBurrito]

I do think that they did something to mitigate another issue. The problem is flow, nitration, emulsion (on long trip that is not an issue), overall temperature of an engine which can induce intake deposits. That is before the fact that additives in oil need certain temperature to properly work.
The fact that coolant thermostat is only 180f instead more common 195f is also indicative of attempt to keep it low.
Like I said, BMW did that trick on N63 to cool off engine bcs. it was hot V design. They had issues with valve stems, turbo lines etc. But even than, they kept it at 195f.

Yeah, I would definitely check things out.

For reference, here is the oil temperature chart from the EPA benchmarking the engine in my CX-50. While not exactly the same setup cause they added a engine oil heat exchanger that was connected to the dyno lab cooling system but was set for 90C. Based on everything I have scene, these engines just don't put a lot heat into the engine oil while crusing down the highway. Plus they have also have relatively large oil capacity at just under 6qt when the engine is brand new, so the oil has a large thermal capacity.

 

[edyvw]

What is oil temperature in the city?

 

[OneLonelyBurrito]

What is oil temperature in the city?

I havent done enough city driving in the cold to have a true idea yet.

 

[KrisZ]

Another variable is the placement of the oil sensor. Some may be placed before the cooler/heat exchanger and some after. It's hard to say and compare to different makes/models.

For reference here is the oil temp that my minivan reports. Because of this discussion I paid attention to it this morning when driving a family member at the airport. The trip is roughly 90% highway and about 1.5 hour long. I just dropped them off and went back home.

One thing to note, was that the oil reached 163F after 20 minutes and then it took roughly another 30 minutes to reach 174F where it stayed.

 

[OneLonelyBurrito]

Another variable is the placement of the oil sensor. Some may be placed before the cooler/heat exchanger and some after. It's hard to say and compare to different makes/models.

For reference here is the oil temp that my minivan reports. Because of this discussion I paid attention to it this morning when driving a family member at the airport. The trip is roughly 90% highway and about 1.5 hour long. I just dropped them off and went back home.

One thing to note, was that the oil reached 163F after 20 minutes and then it took roughly another 30 minutes to reach 174F where it stayed.

View attachment 258049

Is that the 3.6L Pentastar?