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

[Dr_Dr3i]

Our holiday roadtrip to/from FL was about 2600 miles and my oil temps varied between 220-225*F depending on whether we were climbing or descending the hills of Appalachia.

On even ground at steady speeds of 78-80mph on cruise control, every time I looked down the oil temp was 222*F and coolant was 208*F.

These temps are on our 3rd gen EcoD with the 3.0L diesel tuned by GDE.

 

[edyvw]

What exactly is "hot oil"?

212 and up. There is no reason for oil to be below 212. Bcs. additives.

 

[KrisZ]

212 and up. There is no reason for oil to be below 212. Bcs. additives.

OK, let's grant that. Can you point to a white paper or a study showing that's the optimal engine temp? Or are you just basing this on the fact that the SAE viscosity grades are based on this temp?

In regards to additives, are you aware that there are local hot spots that bring the oil temps much higher than the bulk oil temp?

 

[OneLonelyBurrito]

212 and up. There is no reason for oil to be below 212. Bcs. additives.

212 isn’t a realistic temperature target for this engine. It has a 180 degree thermostat stock. Even with a heat exchanger, it would probably only get to 180-190 degrees during the winter. In the 90+ summer weather the oil temp struggles reaches 212 degrees.

 

[edyvw]

212 isn’t a realistic temperature target for this engine. It has a 180 degree thermostat stock. Even with a heat exchanger, it would probably only get to 180-190 degrees during the winter. In the 90+ summer weather the oil temp struggles reaches 212 degrees.

I know. It is surprising and I wonder what made them go with such low thermostat.

 

[TiGeo]

I'm guessing the temp you are watching isn't the correct one. What dies the other temp Channel read?

 

[edyvw]

OK, let's grant that. Can you point to a white paper or a study showing that's the optimal engine temp? Or are you just basing this on the fact that the SAE viscosity grades are based on this temp?

In regards to additives, are you aware that there are local hot spots that bring the oil temps much higher than the bulk oil temp?

I am aware of local hotspots. Those hotspots exist in all engines. Are you aware that engine oil performs perfectly fine at 270-280f in normal engines? That some engines run higher than 300f oil temperature? I tracked BMW at 300f oil temperature “in bulk,” as you would say.
Only thing that comes up to my mind is that Mazda is mitigating some other issue with low oil temperature. It would not be first and only manufacturer to do that. BMW did that on N63 to prolong life of valve stems.

 

[OneLonelyBurrito]

I know. It is surprising and I wonder what made them go with such low thermostat.

It doesn’t seem particularly low. My 2010 Chevy Malibu had a 180 degree thermostat stock. If I were to take a stab at it though, it would probably be knock mitigation during the summer months. Additionally, they also went back to a traditional thermostat on the CX-50 from a coolant control valve they were using from 2018/2019 through about 2023 on similar variants of this engine in different vehicles.

I'm guessing the temp you are watching isn't the correct one. What dies the other temp Channel read?

The estimated oil temperature PID is typically 20-30 degrees higher during the winter. They are closer during the summer months. But I have verified with the Mazda documentation I have been able to find that the oil temp PID I’m looking is the actual oil temperature. I don’t know if it’s from oil level sensor in the oil pan or the combination oil pressure/temperature sensor in the oil galley. But it is the actual temperature.

 

[mbres2000]

I've just now read in several places that engine oil temp should be 215-220, which is hot enough to boil off any condensation. I've never checked it in any of my cars over the years, but my Mustang GT may show it on the "gauges" display. I need to check it out.

Why are people repeating this? The water is not in a kettle to be boiled off. It's emulsified in the oil and will not simply start boiling even if the oil reaches the boiling temp. That temperature, while on the lower side, is perfectly hot enough for the water to evaporate. Water starts to evaporate at 33F, so why would 150F be too low for that?

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.

 

[edyvw]

It doesn’t seem particularly low. My 2010 Chevy Malibu had a 180 degree thermostat stock. If I were to take a stab at it though, it would probably be knock mitigation during the summer months.

The estimated oil temperature PID is typically 20-30 degrees higher during the winter. They are closer during the summer months. But I have verified with the Mazda documentation I have been able to find that the oil temp PID I’m looking is the actual oil temperature. I don’t know if it’s from oil level sensor in the oil pan or the combination oil pressure/temperature sensor in the oil galley. But it is the actual temperature.

Is it drawing temperature from sensors or algorithm?

 

[OneLonelyBurrito]

Is it drawing temperature from sensors or algorithm?

Both are available, but I’m using the actual sensor

 

[fantastic]

Your Mazda is doing well to control the oil temperature.

 

[TiGeo]

180 deg temp thermostats seem to be more of a performance-orientated temp vs. the more typical 195.

 

[tcp71]

The Macan displays coolant temp, boost, oil pressure and oil temperature as you drive. The oil temperature doesn't track outside temperature, it goes to 90C (194f) on initial warm up and then moves from 90-100C depending on engine load. This is at outside temperature from +20C to -24C (coldest I've driven it).

 

[OneLonelyBurrito]

180 deg temp thermostats seem to be more of a performance-orientated temp vs. the more typical 195.

I was just looking on rockauto, it appears Mazda has always used the 180 degree thermostats on there skyactiv engine line with an actual thermostat and not the coolant control valve.

 

[TiGeo]

The Macan displays coolant temp, boost, oil pressure and oil temperature as you drive. The oil temperature doesn't track outside temperature, it goes to 90C (194f) on initial warm up and then moves from 90-100C depending on engine load. This is at outside temperature from +20C to -24C (coldest I've driven it).

Yes, but if you were to collect data, it would still track w/r to ambients i.e. higher when it's hotter/cooler when it's colder out keeping load equal (so say a highway drive test like I did for my data) - see my post above with my graphs, my VW engine is basically the same as what your Macan has.

 

[TiGeo]

Is it drawing temperature from sensors or algorithm?

On the VWs, there are two oil temp values and I can't recall now (will find out) but one is the real one and the other is math and they are not the same. You can see the two in the log. "oil temp mdi" is the one you see displaced and is apparently the "real" oil temp, the other is some modelled value is lower...can't recall what that represents.

Edit. Buddy says these two values track closely but once you mod/ECU tune they don't which is my situation.

datazap.me | Karstgeo72 | GSW rev4c7 beta 2.0 hpfp Uni tune Fastivus log

datazap.me

 

[edyvw]

On the VWs, there are two oil temp values and I can't recall now (will find out) but one is the real one and the other is math and they are not the same. You can see the two in the log. "oil temp mdi" is the one you see displaced and is apparently the "real" oil temp, the other is some modelled value is lower...can't recall what that represents.

Edit. Buddy says these two values track closely but once you mod/ECU tune they don't which is my situation.

datazap.me | Karstgeo72 | GSW rev4c7 beta 2.0 hpfp Uni tune Fastivus log

datazap.me

I wonder the temperature here in high country. Tomorrow I am skiing and it will be -10, which means Gunnison basin will be -20 and below. If is is showing that low oil temperature there, not sure what would be here.

 

[Jetronic]

As long as the oil stays at 80°C I'd be happy. Compared to 100°C the oxidation rate has been cut by a factor of 4, and moisture has no problem evaporating from that. That leaves a good amount of headroom aswell, if needed.

 

[KrisZ]

I am aware of local hotspots. Those hotspots exist in all engines. Are you aware that engine oil performs perfectly fine at 270-280f in normal engines? That some engines run higher than 300f oil temperature? I tracked BMW at 300f oil temperature “in bulk,” as you would say.
Only thing that comes up to my mind is that Mazda is mitigating some other issue with low oil temperature. It would not be first and only manufacturer to do that. BMW did that on N63 to prolong life of valve stems.

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.

Now, if you start looking at much more expensive implementations like in sports cars where they use large oil cooler and thermostats, then yes, the oil temp will be kept close to the 212f mark and will fluctuate very little with the outside temperature. But that doesn’t mean much wider oil temp fluctuations are bad.