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

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Just finished a holiday road trip (~700 miles one way) in my 2023 Mazda CX-50 2.5S. Heading back home on Sunday with my OBD MX+ plugged in, I’m able to monitor all sorts of different parameters on my Mazda including actual engine oil temperature, not just the estimated oil temp. While I don’t know which sensor the data is coming from as Mazda has two oil temperature sensors, one in the ultrasonic oil level monitor and the other is the combination oil pressure/temperature sensor, either way its the actual temperature.

The ambient temperatures started out in the low 30s and only got colder as we traveled North away from the coast and into Appalachian Mountains. For first hour to 90 mins of the drive, the front shutter flaps remained closed and the oil temperature got pretty close to the coolant temp of ~180 degrees, but as soon as the flaps opened up, the engine oil temperature started dropping and dropped all the way down to the high 140s and low 150s when driving on flat roads. Once driving in the mountains, the oil temp crept up, the highest I think it reached with the front shutter flaps opened was mid to high 170s while climbing a long steep grade, but would come back down and settle in the low to mid 160s while not climbing super long and steep grades. This observation has made me curious about the control logic for the shutter flaps, cause once they opened, they never shut again while driving. I figured they would shut while heading down the mountains but they didn’t. This has me thinking this engine might benefit from an engine oil to coolant heat exchanger during the winter months, as one isn’t include.

Just thought this would be interesting to share and was also curious if anyone with the Mazda 2.5T engine monitors their oil temps since that engine has an engine oil heat exchanger included.
 
Thats a little cool for me but I don't think there is any real risk for it.
I don't see any risk either, it would just be nice if it ran a little warmer during the winter. The oil temps are fine during the summer, it will run mid 190s all day. During a heat wave this summer on the same drive, max oil temp was mid 210s to low 220s in the mountains.
Bummer, oil temps too low to boil off water/ moisture contamination. Maybe 30wt oil is not necessary in newer engines after all.
It doesn't appear to have an water/moisture contamination issues, I'm thinking the PCV system is good enough that it can pull most of the moisture and vapor contamination out of the crankcase.
 
Just finished a holiday road trip (~700 miles one way) in my 2023 Mazda CX-50 2.5S. Heading back home on Sunday with my OBD MX+ plugged in, I’m able to monitor all sorts of different parameters on my Mazda including actual engine oil temperature, not just the estimated oil temp. While I don’t know which sensor the data is coming from as Mazda has two oil temperature sensors, one in the ultrasonic oil level monitor and the other is the combination oil pressure/temperature sensor, either way its the actual temperature.

The ambient temperatures started out in the low 30s and only got colder as we traveled North away from the coast and into Appalachian Mountains. For first hour to 90 mins of the drive, the front shutter flaps remained closed and the oil temperature got pretty close to the coolant temp of ~180 degrees, but as soon as the flaps opened up, the engine oil temperature started dropping and dropped all the way down to the high 140s and low 150s when driving on flat roads. Once driving in the mountains, the oil temp crept up, the highest I think it reached with the front shutter flaps opened was mid to high 170s while climbing a long steep grade, but would come back down and settle in the low to mid 160s while not climbing super long and steep grades. This observation has made me curious about the control logic for the shutter flaps, cause once they opened, they never shut again while driving. I figured they would shut while heading down the mountains but they didn’t. This has me thinking this engine might benefit from an engine oil to coolant heat exchanger during the winter months, as one isn’t include.

Just thought this would be interesting to share and was also curious if anyone with the Mazda 2.5T engine monitors their oil temps since that engine has an engine oil heat exchanger included.

And people think their oil gets to the same temperature in winter and summer, while in reality they amost track perfectly with ambient temperatures. Thanks for this.

The turbo is likely to put more heat into the oil, I suppose by about the same amount that the cooler removes. Only at high boost situations of course. I'd expect the winter oil temps to be slightly higher, in summer closer to what you see.
 
Thanks for the data. Seems the Mazda has good oil cooling. Probably would be perfect for some laps. My 18 Outback has an oil temp gauge in the infotainment center. In the winter I run 190-210. In the summer 210-230s. I live in mountainous terrain.
 
Any way to get an aftermarket control for the shutters? I'd think a small electronic device would be cheaper and easier to install than an oil cooler.
I did some digging on Mazda's control logic for shutter flaps, at least for a Mazda3 not the CX-50 but I imagine it would be similar since I couldn't find anything on the CX-50 yet. The control logic has two checks that might have been keeping them slightly open. First is a throttle valve protection mode designed to prevent large amounts of crankcase gases from freezing on the throttle valve because with the flaps closed. Engine oil temperature supposedly increase rapidly. 🤷‍♂️ Second is A/C line pressure, but I didn't have the A/C on and the HVAC control was set to manual mode. While it may have been running the A/C in the background, I did everything I could to keep it off.

I think it would be easier to add a sandwich heat exchanger that goes between the engine and the oil filter then to mess with the control logic of the shutter flaps. I will have to do some digging to see if Mazda included one on any variant of their naturally aspirated 2.5L.
Sounds like electronic coolant control valve has taken a dump. Mazda has a fix for it, and a warranty extension to 150K. Your temps should not move, especially that much.
The CX-50 doesn't use a coolant control valve, just a traditional thermostat. The coolant temps were fine at ~180 degrees, I was only talking about the engine oil temp.
And people think their oil gets to the same temperature in winter and summer, while in reality they amost track perfectly with ambient temperatures. Thanks for this.

The turbo is likely to put more heat into the oil, I suppose by about the same amount that the cooler removes. Only at high boost situations of course. I'd expect the winter oil temps to be slightly higher, in summer closer to what you see.
Just cruising down a flat interstate, I don't think the turbo would be adding a ton of extra heat into the oil. So I would imagine most of a oil temp increase would be due to the engine oil heat exchanger, not the turbo. While in boost, when the engine is under heavier load, the turbo would definitely increase the oil temperature. But on a flat road like my first section of driving when my oil temps dipped into the 140s, I have my doubts.
Moisture will still evaporate out of the oil even if the oil temperature doesn’t reach 212F. It just takes longer.
I was thinking more along the lines of evaporating out the heavier components of gasoline that makes it into the engine oil. Moisture doesn't seems to be a problem, as the engine doesn't even get a hint of moisture sludge on the oil fill cap during the winter.
 
Bummer, oil temps too low to boil off water/ moisture contamination. Maybe 30wt oil is not necessary in newer engines after all.

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?
 
i used a Hyuandai/kia oil cooler from. 12’ optima on my accords. mounts to the filter pad with the kia adapter bolt and your filter screws on like normal. i can feel the supply and return coolant hose temperature deltas when warming it up in the morning.

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i used a Hyuandai/kia oil cooler from. 12’ optima on my accords. mounts to the filter pad with the kia adapter bolt and your filter screws on like normal. i can feel the supply and return coolant hose temperature deltas when warming it up in the morning.
Thanks for the heads up, that will be something to look into. I don't think I would do it while under the powertrain warranty, but once that is expired, I may try and add it.
 
I'm quite sure the engineers at Mazda understand oil temp requirements and this is all perfectly normal and ok. It's a NA engine so oil temps will never be like they are on a turbo'd engine. The "water boiling off" thing is silly. If that oil is at the temps indicated, it's ok.
 
I'm quite sure the engineers at Mazda understand oil temp requirements and this is all perfectly normal and ok. It's a NA engine so oil temps will never be like they are on a turbo'd engine. The "water boiling off" thing is silly. If that oil is at the temps indicated, it's ok.
Oh I'm not concerned in the slightest with the oil temps, I just thought it would be interesting to share here and keyboard engineer, oh I mean discuss :LOL:, the data I have collected.
 
In the age of CAFE chase for every 0.00001mpg, that is too low.
Hiking up oil temperature is easiest way to achieve efficiency. Does that engine have heat exchanger between coolant and oil?
 
In the age of CAFE chase for every 0.00001mpg, that is too low.
Hiking up oil temperature is easiest way to achieve efficiency. Does that engine have heat exchanger between coolant and oil?
It does not have a coolant-oil heat exchanger. The oil pump is completely variable though, typically the oil pressure is 21psi until the engine load increases.
 
It does not have a coolant-oil heat exchanger. The oil pump is completely variable though, typically the oil pressure is 21psi until the engine load increases.
To be honest, in today day and age CAFE everything, I am really surprised it doesn’t have heat exchanger. It would benefit in winter and summer.
IMO, that is too low. Hot oil is always best oil.
 
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