2015 CX-5 2.5L SkyActiv coolant in oil

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2015 CX-5 GT
At 88k miles, Blackstone report suddenly shows 10x normal level of Sodium and nearly 100x Potassium - clearly, coolant in oil. I have searched the internet and cannot find any other mention of this situation in the 2.5 SkyActive engine. Of course, with 13:1 compression the first suspect is the head gasket. However, there are no bubbles emanating from the radiator and the chemical (block) test shows no evidence of combustion gases in the coolant. The next thought for any engine would be the oil cooler, but this engine doesn't have one. I'm familiar with the water pump issues from (completely different, Ford-sourced) Mazda engines but the exploded view in TSB01-022/19 (https://static.nhtsa.gov/odi/tsbs/2019/MC-10169537-0001.pdf) seems to make this pump an unlikely source for transfer into oil.
Does anyone have experience with this situation, in this engine?
Since many are probably wondering....no expense has been spared in the care of this engine - always 89 Octane to mitigate possible detonation and 5k oil changes (not every one analyzed) with LiquiMoly SpecialTecAA 5w30. Spark plugs replaced at 71k.
Blackstone report shows no damage yet, but I'm keenly aware of the seriousness of this condition. I've already changed the oil again after only 2600 miles and sent that for analysis also. Credit to Blackstone for saving this engine!
It may well still be the head gasket, but I'm looking for something more definitive before I spend that $ unnecessarily.
What say you, Mazda Gurus??
Blackstone report:
https://www.mazdas247.com/forum/ind...iv-oil-analysis-thread.123854237/post-6716760

*Congratulations, Team Mazda! -- 3rd Place DPi Class (and overall) 2021 24 Hours of Daytona
 
Well you certainly will want a confirmation of the report, because anyone, Blackstone included, can make a mistake. But if the next report comes back looking the same, then you should do a compression and leak down test, in order to find out what's actually happening with you vehicle's engine and how bad the problem currently is. Then, depending on those test results, you'll need to decide what to do next.
 
Minimal coolant loss, well within the "steam released from water pump" described in the TSB.

Thanks also, Edmaz - I'm still waiting for the results of the confirmation test from Blackstone.
 
Bear in mind that even a very small coolant leak can dillute the oil.
Although we havent seen many coolant issues/reports here but also not many people do UOA so..one never knows the stats.
As mentioned in the other thread try a 2nd test at a different company.
 
I have a 2014 CX-5 2.5L SkyActive and just got back a UOA from Blackstone Labs that shows 681 ppm potassium, 267 ppm sodium, and 0.53% antifreeze. I had not had a UOA run in a couple of years, but decided to do so because I recently passed 100,000 miles.

I am also meticulous about maintenance (as I suspect most are who bother to run UOAs), and I've noticed no loss of antifreeze.

Fortunately, the UOA shows no unusual metal wear, so either I caught it early or the test result could be in error.

DaveIndy, what do you mean when you say, " I'm still waiting for the results of the confirmation test from Blackstone." Do they re-run the sample upon request? How does this work?
 
... I've noticed no loss of antifreeze. ...
Although it was posted previously, I'll also suggest that one or both of you try another lab for your next test. IMO it now appears to be likely that something is not right with what Blackstone is doing.
 
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I have a 2014 CX-5 2.5L SkyActive and just got back a UOA from Blackstone Labs that shows 681 ppm potassium, 267 ppm sodium, and 0.53% antifreeze. I had not had a UOA run in a couple of years, but decided to do so because I recently passed 100,000 miles.

I am also meticulous about maintenance (as I suspect most are who bother to run UOAs), and I've noticed no loss of antifreeze.

Fortunately, the UOA shows no unusual metal wear, so either I caught it early or the test result could be in error.

DaveIndy, what do you mean when you say, " I'm still waiting for the results of the confirmation test from Blackstone." Do they re-run the sample upon request? How does this work?
Sometimes no loss of coolant doesn’t mean your head gasket is fine. It’s a 2-way street, either oil gets into your cooling system, or the coolant gets into your oil, or both. A compression test can tell more stories on your engine.
 
Sometimes no loss of coolant doesn’t mean your head gasket is fine. It’s a 2-way street, either oil gets into your cooling system, or the coolant gets into your oil, or both. A compression test can tell more stories on your engine.
I understand and agree completely. However, I did have a 99 Tahoe that needed two head gasket replacements, and both times I saw the need for makeup antifreeze.

I have been in contact with my mechanic and will definitely go with a compression test before looking to do a gasket replacement. Not cheap!
 
I understand and agree completely. However, I did have a 99 Tahoe that needed two head gasket replacements, and both times I saw the need for makeup antifreeze.

I have been in contact with my mechanic and will definitely go with a compression test before looking to do a gasket replacement. Not cheap!
You may try another OUA from different vender as suggested by others before you decide to do something major to your engine. You should also consider a used engine with less miles from salvage yard if the cost is not much higher.
 
The idea of a "confirmation" test came from other posts. Of course, an error is always possible but not what I was trying to determine. The second test was done at half the previous drain interval because the oil had been changed every 5k miles but the last analysis was done 27k miles ago. The second test is to help me decide between the following 2 choices:
A) Since the engine has 90,000 miles on it, if the leak is small an option is to just keep changing the oil more often. Of course this is not ideal but this car is now a seldom-used 3rd car in our family. With no increase in wear metals or serious viscosity breakdown, choosing not to spend thousands of dollars is an option.
B) If I choose to spend $1500 on a new head gasket, I'm certainly not going to pay what is nearly all labor $ to put belts, tensioner, hoses, etc with 90k on them back on the car. This choice would be a life-extending preventative maintenance investment of approx. $2k.
The second test showed exactly half the amount of K and Na, at half the change interval. For me, this is confirmation that both test are accurate. For the record, I have complete confidence in Blackstone. I know lots of people who rely on them for aircraft and automotive/diesel engine monitoring and have never heard of them producing bad test results, ever. I also switched oils from SpecialTec AA to MolyGen to prove that it was not a problem with the oil. I'll post the Blackstone report on the UOA thread, along with some interesting Qs and As from Blackstone.
For now, the car is going in for a compression test (thanks, Edmaz) and a cooling system pressure check (Blackstone's rec). I'll report those results ASAP.
Thanks for your response, RPF -Good luck to us both!
 
.... For now, the car is going in for a compression test ...
Given that you described the coolant loss as 'minimal', I recommend asking the shop to do a leak down test along with the compression and pressure tests. IMO it's likely the compression numbers will be fine, and will not indicate an issue. However, the leak down test may possibly provide a different perspective. With all the work already done to remove the plugs, they hopefully won't charge a huge extra amount to do the additional test.

That said, I'm totally mystified that Blackstone describes this as a 'fairly severe coolant leak', when you're not seeing anything close to that when checking the coolant level. 'Fairly severe' to me means adding make up coolant regularly, but perhaps their perspective about coolant in the oil is different than mine. This entire thing is very puzzling to me, and I'm definitely interested to see how the results of all the other testing turns out.
 
Ok, thanks - I'll ask for the Leak-down test too.
I agree..."Fairly Severe" would seem to be at least some visual indication in the oil. However, being oil experts, any amount of coolant in oil is probably alarming to them.
I'll report back next Fri with some more clues.
Thanks to everyone who has responded!
 
Ok, thanks - I'll ask for the Leak-down test too.
I agree..."Fairly Severe" would seem to be at least some visual indication in the oil. However, being oil experts, any amount of coolant in oil is probably alarming to them.
I'll report back next Fri with some more clues.
Thanks to everyone who has responded!
So you can’t see any pinkish color in your oil? Can you see any oil floating on top of the coolant when you open the radiator cap with cold engine?
 
Incredibly, No-
No sign of anything unusual in oil, not even a sheen on the top.
I pushed a paper towel into the coolant reservoir, hoping to catch any little bit of slime that might be in there, and wiped the dip tube. Nothing.
When performing the chemical block test, I drew some coolant out with a white rag (as directed to prevent detection fluid from being contaminated with coolant). Coolant came out perfectly blue and clean as new.
 
⋯ I pushed a paper towel into the coolant reservoir, hoping to catch any little bit of slime that might be in there, and wiped the dip tube. Nothing.
How about just open the metal radiator cap itself and check any sign of oil floating on top the the coolant?
 
The chemical test is done directly from the radiator. That was the part referencing a white rag, above. Didn't want to risk the paper towel coming apart in the radiator.
 
Sorry for the delay, here's how this situation has progressed:
A cylinder leak-down test was done because I wanted to determine the viability of the engine (weather it is worth spending $ on). The tests showed Zero leak-down at both cold and at normal operating temperature. To me, this suggests that the leak is either minuscule or elsewhere. The next suspect would be an oil/coolant heat exchanger (oil cooler) but, from what I can determine, this engine doesn't have one.
Next, I decided to use Bar's Leaks Cylinder Head Fix. As expected, the heater core degraded to approx. 50% efficiency. After 500 miles, a chemical flush was used to remove the excess Bars Leaks sealer (Prestone makes a good chemical flush). After 100 additional miles, the cooling system was flushed with new coolant to remove the chemical flush. The heater is now about 80% effective, compared to new. An oil/filter change was done (but not analyzed) as a clean-out prior to further testing.
After 1240 miles, another oil/filter change was completed and the oil was sent for analysis. The report indicated a major reduction in Potassium and a significant reduction in Sodium. The report is attached.
Currently, another 2500 miles have passed and I'm ready to change/analyze the oil again. This should be the final answer as to weather the problem has been fixed. I'll post that Blackstone sheet as soon as I receive it.
 

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