2024 Mazda CX-90 I-6T Factory Fill 1st OCI

[cammyfive79]

We own this same vehicle and are coming up on 15K miles; I have yet to do a UOA on our particular CX-90 but found this on a forum I visit. While the engine is obviously breaking in still, what does everyone make of the 2.5% fuel contamination at this very early age? We've been doing 6 month/5k mile OCI so far and are due for another one in maybe 3 weeks so I'm curious what inferences anyone can see from the UOA on this pretty much brand new engine

Oil Analysis

www.cx90forum.com

 

[Titan]

It's Blackstone...they don't do a gas chromatograph technique for fuel...so they are just guessing.

 

[OneLonelyBurrito]

With it being blackstone, we have to take the fuel dilution number with a grain of salt typically. But I think in this instance, we can conclude there is well over 2.5% fuel dilution with this sample. I would imagine that number would come down in later UOA's as the ring pack seats. Based on the comments on the post it sounds like the vehicle doesn't get driven a lot ~5k miles per year. So I not surprised by the amount of fuel dilution that is being reported.

 

[tolian21]

I bet fuel dilution is much higher than 2% since viscosity is 6.1 cSt

 

[cammyfive79]

I bet fuel dilution is much higher than 2% since viscosity is 6.1 cSt

Ahhhh, I see. Looking forward to sampling ours in a couple of weeks when it hits 15K miles.

 

[Glenda W.]

Looking forward to you uoa. Thanks

 

[himemsys]

We own this same vehicle and are coming up on 15K miles; I have yet to do a UOA on our particular CX-90 but found this on a forum I visit. While the engine is obviously breaking in still, what does everyone make of the 2.5% fuel contamination at this very early age? We've been doing 6 month/5k mile OCI so far and are due for another one in maybe 3 weeks so I'm curious what inferences anyone can see from the UOA on this pretty much brand new engine

Oil Analysis

www.cx90forum.com

I'd use Oil Analyzers. They use gas chromatography, which gives a more accurate assessment of actual fuel in the oil. They guess based on flashpoint and viscosity, rather than actually measuring the percentage of fuel in the oil. From my experience looking at UOAs, I agree with @tolian21 in that that 2.5% is actually closer to 5-6%. That doesn't mean you will get the same results in your CX-90. When you take your sample, make sure you give it a good ~30-50 mile drive before you drain and sample the oil. This will give any residual fuel from cold starts and idling a chance to burn off.