2024 6.6 Fuel in oil

[Cappy74]

I have a 2024 6.6 started out with no issues and now fuel in with my oil. The first 15k miles all good, but now 5.1% fuel and one time as much as 7% in with the oil. I know most dont oil analysis, but looking to see if anyone else is having issues?

I attached the PDF form Polaris Labs with 8 samples on it. Take a look any input or similar information would be helpful.

Thank You

Kevin

 

[2004LB7]

Welcome

That was an issue in the LB7 with the first generation injectors. The body would crack and leak fuel into the crank case. I don't know 5 or 7% fuel is normal or too much but obviously less is better.

Another issue is cylinder washing and potentially getting fuel past the rings into the oil. More related to the LMM with its regen strategy. I wouldn't think the L5P would have that issue with. Unless it's tuned with really low timing or excessively long pulse

Maybe a leaking injector? How do the balance rates look?

I would think a 2024 would still be under warranty. Have you checked with your dealership? Or called GM/Chevy for help?

 

[Cappy74]

2004LB7,

Thanks for the insight. At this time it's in the dealers hands. It took me this long to get them to look at it. The issue was with no check engine light they kept sending me away. I finally pushed and they got a regional rep to okay doing some test. I don't know what test they have done, but they are saying that they don't see any issues. I have the data that says otherwise.

I'm and oil guy. 3% or more is an issue with fuel in oil. At 10% its should be changed ASAP. The viscosity of the oil will start to fail. The saving grace is I change oil at 5K miles and that is not even 50% on the change oil monitor.

Cappy

 

[2004LB7]

That percent sounds reasonable.

The issue will be what the manufacturer says is the acceptable limit. Don't know if anyone here has that data.

 

[Cappy74]

2004LB7,

Fuel in oil is an industry standard so the question is why is it not seting a check engine light, what is GM using for the guidelines on that. I think they are at a loss since most people do not do oil analysis on 6.6 duramax trucks, but its what I do.

Cappy

 

[2004LB7]

2004LB7,

Fuel in oil is an industry standard so the question is why is it not seting a check engine light, what is GM using for the guidelines on that. I think they are at a loss since most people do not do oil analysis on 6.6 duramax trucks, but its what I do.

Cappy

There is only two sensors for oil. Pressure and level. There is an algorithm in the ECM that uses, pressure, engine temperature, run time, engine load, miles, and probably more to calculate if the oil is still good. Oil will typically be thin(er) when new. Then slowly thicken as it loads up with ash and wear particles. Then as it continues, it will start to shear the oil chains and the oil starts to thin again. The ECM can see this happening to some degree based on cold and hot running pressure and trigger the oil life monitor. So, if the fuel in the oil doesn't cause enough thinning the ECM will not flag it. It's possible the thinning will be faster then the algorithm is designed to work with too. In general, fuel in oil is not something the engineers decided was important enough to program in or have extra sensors for. Or the been counters keep it out

Normally fuel in oil levels are kept at acceptable levels with the standard oil changes

 

[Cappy74]

I think you are spot on! The level of fuel is ahead of the algorithm and the 5k oil change is also a factor. The CK-4 platform is very good at keeping oil in grade. It would be hard to get the oil to thinken with this amount of fuel being introduced to the oil. Maybe we there is someone else in the group that has some data or some knowlege of these news injectors and maybe some issues. It's hard for me to say since I don't know yet what test they did, only that they sent the data to GM.

 

[malibu795]

If something does go wrong you have receipts.
Service technician should be able to pull up fuel dilution limits.
Did you ask them to send the data to GM?

 

[TheBac]

Moved this over to the L5P section.

 

[Cappy74]

Moved this over to the L5P section.

It looks like yo did, thank you!

 

[Cappy74]

If something does go wrong you have receipts.
Service technician should be able to pull up fuel dilution limits.
Did you ask them to send the data to GM?

The technicians have not shared with me what GM says the limits are for fuel dilution. The flags in the report are from the lab and they get them from the OEM. They have just started sending data to GM, but I've asked to have the same data or information of the data and I have not been givin it yet.