Mag1 Ow20 - 8,951 Miles - '16.5 CX-5 w/ 2.5l

[RamFan]

After being on the site for years I finally decided to run a UOA. With a new Mazda that has a new (to me) OLM, I figured it was the perfect time. I first changed the oil at the 1,169 mile mark to get any of the immediate wear materials out of the engine. After seeing the results of this change, I'm doubling down on that practice (unless told otherwise from the manufacturer).

This is my first Mazda with an OLM. I had a '14 CX-5 with the same motor but the manual only allowed for 7.5k mi/6 month or 5k mi/4 month OCIs, given that it was under warranty that is what I adhered to. The new CX-5 gives a third option, a OLM option. Given that I use the OLM in the Monte and that I like to stretch every dollar I naturally decided to simply follow the OLM and be done with it. The only caveat to the OLM is that if the indicator does not illuminate but you've reached 10k miles or 12 months, then it's time to change the oil. Well, I reached 8,951 miles in approximately 4 and a half months and the OLM still read 60%. I decided it was time to do an oil change and get a UOA.

Other than the initial wear, everything looks good. I think I'll run my next change for around the same amount of miles and get a 2nd UOA to see if the numbers start trending downward. If they do, I think I'll be hitting the 10k mile cap in no time.

 

[MolaKule]

So you changed out the factory oil at about 2800 miles which is good.

Replace it Mag1 again and sample at 5000 miles.

 

[RamFan]

Changed the factory at 1,169. Replaced it with Mag1, unfortunately I didn't have any Mag1 on hand for the 2nd oil change. Used Mobil Super Syn instead.

 

[zeng]

Well built engine, you have.
Used viscosity a tad low, otherwise this oil looks good.

 

[badtlc]

Things look fine. If you wanted to fix the fuel dilution (you do not need to), running premium gasoline will completely eliminate it and keep that viscosity at its original level.

 

[jaynissan12]

How do you figure?? if the engine is designed for 87 octane, running 91-93 octane isn't going to do a thing for it. DI will get fuel in the oil not matter what, just part of the design flaw.

 

[badtlc]

Originally Posted By: jaynissan12
How do you figure?? if the engine is designed for 87 octane, running 91-93 octane isn't going to do a thing for it. DI will get fuel in the oil not matter what, just part of the design flaw.


Not quite and I have evidence of it. See my skyactiv UOAs.

This is how high compression DI engines work on 87. To prevent detonation under these higher pressures, the ECU is programmed to run extra rich. The extra fuel in the combustion chamber cools the chamber and prevents detonation. This excessive fuel trim ends up putting a lot of fuel in the oil.

If you run higher octane, the ECU leans the A:F mixture accordingly. This is not new or special technology. I think all flex fuel vehicles have had this capability for a while.

There are many UOAs of skyactiv engines (but this applies to all high compression DI engines) showing if you run premium, that oil will stay in grade. In my cases, the UOA showed a viscosity the same as VOA.

 

[UltrafanUK]

Although it might be worth trying high octane fuel, I would just cut the OCI to 5K miles to see if the figures improve.
Fuel contamination is not good news if you are using an 0w20 and longish OCI's and although the engine is still running in to some extent, the Fe does seem a bit high in comparison to the universal average. If the wear metals don't trend down in the next OCI, I would be inclined to try changing to an 0w30.

 

[zeng]

Why would a 13.0 compression ratio gasoline engine is said to be designed for 87 octane fuel ?
Does manual recommends so, just curious ?

 

[artificialist]

Originally Posted By: zeng
Why would a 13.0 compression ratio gasoline engine is said to be designed for 87 octane fuel ?
Does manual recommends so, just curious ?

The manual does call for 87 octane, but some engines perform better with octane levels higher than what is in the manual.

Direct injection is partially why 87 octane can be used. The other reason is that the exhaust system is very efficient. It is like having the low exhaust backpressure of long tube headers yet the fast catalyst light-off time of cast iron exhaust manifolds.

There was another Skyactiv-G engine that had cast iron exhaust manifolds, but it had to have 12.5:1 compression in order to use 87 octane gasoline.

 

[zeng]

Originally Posted By: artificialist
The manual does call for 87 octane, but some engines perform better with octane levels higher than what is in the manual.
Direct injection is partially why 87 octane can be used. The other reason is that the exhaust system is very efficient. It is like having the low exhaust backpressure of long tube headers yet the fast catalyst light-off time of cast iron exhaust manifolds.
There was another Skyactiv-G engine that had cast iron exhaust manifolds, but it had to have 12.5:1 compression in order to use 87 octane gasoline.

Thanks heaps.
In view of the high drop in KV@100 values, I concur with badtlc that a higher octane fuel should be considered for use here.