SkyActiv Oil Analysis Thread

There was another report few months back for coolant in the oil and a separate forum thread but no replies after February on the subject.
The general advice was to first do 2nd test at different lab. Small quantity of oil sample can be taken out through the dipstick tube. i.e from the new oil at present without the need to change or take it out.

Thanks for sharing! I'll probably do an analysis from Blackstone labs this time to confirm if it's indeed a coolant leak. Hopefully my car isn't toast lol
 
I did my oil analysis at 73K and apparently there's a coolant leak. I brought my vehicle to a mechanic 2 months ago and he did a pressure test but did not find any sources of a leak so I am not sure. I did put some UV dye in the coolant reservoir to see if the funny smell coming from my heater was due to a heater core leak but there wasn't anything noticeable.

So a blown head gasket?

Have you ever over heated it?
 
So a blown head gasket?

Have you ever over heated it?

Never overheated anything but the coolant leak I'm referring to is from the oil analysis. I'm planning to submit another sample to Blackstone labs to confirm before taking any action in addition to performing a visual inspection.

Others have suggested to perform a pressure test as well which I may attempt.
 
Coolant in the oil would indicate a head gasket breach. How's the oil looking on the dipstick, milky light brown at all? How's the coolant look in the radiator and overflow bottle? Any signs of oil slick in the liquid?
 
Coolant in the oil would indicate a head gasket breach. How's the oil looking on the dipstick, milky light brown at all? How's the coolant look in the radiator and overflow bottle? Any signs of oil slick in the liquid?
Thanks for the list of things to check for, I will be sure to take a look at all of those items that you listed and post an update.
 
Last of the included "30k miles of free service" on our 2019 North American diesel. I'll be doing service myself from here on out.

Still continues to run fantastic. I love it. Great efficiency and power.

Latest UOA. There does seem to be a correlation between how many miles after a regen cycle and when the oil sample is collected for analysis on how much fuel shows up. Needs some time to burn off the fuel that gets in the oil. I know the two previous samples were not long after regen's and this latest one was hundreds of miles after a regen ...
 

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So I found some samples I forgot to send in from like 2019 and 2020 (and am about to do a service probably this upcoming weekend). Are those too old to send in now or does it matter?
 
So I found some samples I forgot to send in from like 2019 and 2020 (and am about to do a service probably this upcoming weekend). Are those too old to send in now or does it matter?
IMO it shouldn’t matter. However those are things of past. You want to send in the most recent used oil to find out the current engine conditions. UOA for previous oils can only be used for comparison purpose and satisfy the curiosity.
 
@ColoradoDriver , I believe the samples would be fine if they've been sealed up tightly in their bottles. Question is, what is your purpose for testing the samples and is it worth the cost to you to have the historical trend data.

Another option would be to send in a current sample when you do your service and see how that comes back. If all is normal, continue on with life. If something comes back weird, then it may be worthwhile to send old samples in to see when things changed.
 
IMO it shouldn’t matter. However those are things of past. You want to send in the most recent used oil to find out the current engine conditions. UOA for previous oils can only be used for comparison purpose and satisfy the curiosity.

@ColoradoDriver , I believe the samples would be fine if they've been sealed up tightly in their bottles. Question is, what is your purpose for testing the samples and is it worth the cost to you to have the historical trend data.

Another option would be to send in a current sample when you do your service and see how that comes back. If all is normal, continue on with life. If something comes back weird, then it may be worthwhile to send old samples in to see when things changed.
OK, that makes sense. I'll just send the most recent and go from there. Its from when they redid my pan in November. So not sure its all my oil. I had one jug (last one) of 0w20 that I gave them when they did the job. Figured winter was the best time to get rid of the last of the 0w20. Will be putting in my last jug of 5w30 PP in my upcoming change.

Then will be the GF-6 5w30 from here on out.
 
my latest used oil analysis.
CX5 2.5 2018 non turbo, MazdaMoly 0w20 oil used since day 1.

Nothing new in the report. Normal as usual except the viscosity and flashpoint are a tiny bit lower than before. Most likely due to the extreme heat Phoenix had in the past months.

20210715_000544.jpg
 
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my latest used oil analysis.
CX5 2.5 2018 non turbo, MazdaMoly 0w20 oil used since day 1.

Nothing new in the report. Normal as usual except the viscosity and flashpoint are a tiny bit lower than before. Most likely due to the extreme heat Phoenix had in the past months.

View attachment 301201
Mazda moly 0W-20 oil?
 
Yes. The usual suspect :)
I am having a suspicion this oil is not so good for extreme heat and more than say..5000 miles in such conditions.
Tempted to try 5w30 but not sure about the US powertrain warranty after.
 
Yes. The usual suspect :)
I am having a suspicion this oil is not so good for extreme heat and more than say..5000 miles in such conditions.
Tempted to try 5w30 but not sure about the US powertrain warranty after.
You can always try GF-6 0W-20 oil until you have run out the powertrain warranty. Then go for GF-6 5W-30 in hot Arizona. After all Mazda recommends 0W-20 AND 5W-30 oil worldwide on SkyActiv-G 2.0L / 2.5L anyway.
 
Yes. The usual suspect :)
I am having a suspicion this oil is not so good for extreme heat and more than say..5000 miles in such conditions.
Tempted to try 5w30 but not sure about the US powertrain warranty after.
Why do you think this is the case? Normal operating temp for engine oil is in the 230 to 250°F range. Would ambient temps ~20° higher there than in my area (110's vs. 90's here) make that much difference in oil life? I doubt that air temps would really change engine oil operating temperature all that much. I know on my Miata where I monitor coolant temp with an OBD2 dongle and phone app, coolant temps stay in the low 190's in the dead of winter, and upper 190's in the heat of summer. Less than 10 deg. difference with a 70 deg. ambient air difference between seasons. So the heat inside the engine stays nearly constant all the time.

I guess we would have to see the UOA from that oil used in Arizona heat for ~5K miles to know for sure. I've used Mazda Moly 0w-20 oil for as much as 8K miles on one fill, and Blackstone even recommended that I could go 10K miles based on the viscosity readings. But I haven't pushed it that far. I've just been changing it after 6K to 8K miles.
 
my latest used oil analysis.
CX5 2.5 2018 non turbo, MazdaMoly 0w20 oil used since day 1.

Nothing new in the report. Normal as usual except the viscosity and flashpoint are a tiny bit lower than before. Most likely due to the extreme heat Phoenix had in the past months.

View attachment 301201
I had to do a double-take on your oil change intervals. Are you really changing your oil every 2500-3500 miles?! That seems kinda excessive on a vehicle that calls for 7500 mi oil changes.

There is no problem using the full synthetic Mazda moly oil for 5000, 7500, or probably even 10k miles
 
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