Here is the latest UOA for my Mazda CX-50 2.5S (N/A 2.5L). Please enjoy the information overload.
The oil was in use from Dec 24th 2023 to July 24th 2024. Over that time I covered 9771 miles, which included approximately 4400 miles in road trips. Otherwise the this is our run around vehicle, so gets a good mix of driving including some short trip along side some longer trips. According to the computer, this run had 255 hours on it with 26 of them being idle hours. 355 gallons of gasoline were consumed with an average MPG of 27.6 with an average speed of 38.3mph. Highest MPG was 32.5 and the lowest was 22.5. The average engine power output per hour of use was 18hp (3438kWh or 4607hp-hr). The OLM was showing 600 miles remaining at the time of the change but was showing that with every restart for about 300 miles, so I would have expected to be going to zero at about 10000 miles.
The oil used was Pennzoil Platinum 0W-20 with a Mazda filter, 1WPE-14-302 and was replaced with the same thing. A little bit of oil was consumed over the OCI, but it was probably in the range of 1/8-1/16 of a qt, so nothing to be concerned with. The max engine oil temperature I saw was in the 215-220 range when driving through the Mountains of West Virginia in 90+ degree heat. In most other driving situations, the 2.5L Skyactiv engine doesn’t appear to get its engine oil all that hot. When the ambient temperature is in the 60s, the engine oil temperature might not even reach 180 degrees with an 1 hour of driving at highway speed.
Now on to my thoughts about the UOA. I think the Pennzoil held up much better than the oil the Mazda dealership used. Wear metals are stabilizing and the final break-in metals, Cooper mostly, appear to be out of the system. The oil appears to have held up well, viscosity is still in the correct range, although down a little bit from PP 0W-20 starting point. TBN appears to have held up at 2.2, when the starting point is 4.8. Oxidation at 11 is only 5 points above Platinum’s starting point of 6. Although I couldn’t find a starting point for the Nitration value of PP 0W-20, I’m assuming it probably similar to the PPHM 5W-30, which had a starting nitration value of 5, so mine would be about 5 points above that. All acceptable in my book. Fuel dilution at 2.5% is acceptable level to me. I do think it’s probably is quite hard to get fuel dilution much lower then that given the N/A Skyactiv engine oil appears to be quite slow to warm up.
I took this oil sample after driving home from work. When I checked my oil temperature, it was 192 degrees after I had been driving for about 1.5hr as traffic was horrific that day. Hope you enjoyed this ramble, let me know your thoughts.
I’m planning on following the OLM for the next change after seeing this. Although, I don’t anticipate this OCI having 4400 miles of road trips. So, the next oil change will probably be Spring 2025.
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