Gaining Oil - Fuel Dillution - Some Thoughts

[JLUR Farout]

Good Evening,

For many months I have been dealing with my 2.0L powered 2024 JLRX gaining oil. I have tons of documentation, oil analysis, pulled samples and let them sit to see and smell the gasoline. We have several vehicles and only my oil smells like gasoline. Dealer inspected months ago, finally the part came in and Friday I get it installed. Dealer thinks it is the o-ring on the back of the fuel pump that is bolted to the engine block. We will see. I have done multiple cans of SeaFoam at once and a can each tank to ensure the injectors are clean. No real change in average MPGs per my spreadsheet of each fill-up.

Two things I have found that seem to cause a spike / growth / increase in the dipstick reading for the engine oil. One is running 87 octane, which sucks because I live in eastern WA where 87 is circa $4.00 per gallon and 91 (not much 93 around me and none on my work route of 63 miles one way) is at or above $5.20 per gallon. The second thing is putting around, such as on forest roads or gravel roads. NOT idling, but just driving without much engine load. These are my OCD observations. Regular driving, towing or not, and running 91 seem to really mitigate the engine oil growth. I've done a lot of frequent engine oil changes since the late fall.

Anyone else notice something similar to what I am observing?

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[CarbonSteel]

The 2.0T is a direct injection engine and is prone to fuel dilution. Have you performed a used oil analysis to find out what the dilution percentage actually is?

You will have to find a lab like Polaris that uses gas chromatography as the test method. Blackstone does not use it and their results will not be accurate.

 

[NWJeepr]

You've probably already ruled this out, but if you check the oil level on the dipstick when the engine is cold and turned off, the reading is falsely high... make sure you're following the 2.0 oil check procedure in the owner's manual.

I notice the smell of fuel in the oil from my 2.0, but that's all direct inject engines I've owned. I'm not getting noticeable fuel volume added to the oil.

What percentage is your fuel dilution at, how many miles? How much fuel is being added to the oil?

 

[JLUR Farout]

@CarbonSteel and @NWJeepr, please see below. These are pictures / slides I made to send off to the dealer last month. I have a lot of other hand-written notes in my maintenance book but that is out in the garage.

I have trialed so many dip stick reading ways it is not funny. What I have found that is the most reliable is to have the engine sit at least 4 hours, but usually 12 hours, on level ground. Pull the stick and read it. The five minute mark, stick in or stick out, is not precise. It can read high or low.

 

[CarbonSteel]

Buy one of these and send in a sample. Blackstone uses a highly subjective flame test that is not accurate.

Polaris uses gas chromatography and is the most accurate test out there.

https://www.amsoil.com/p/oil-analyzers-test-kit-non-postage-paid-oainppkit/

 

[NWJeepr]

Measuring oil drain volume is a good investigative step versus just relying on the dipstick. As we know, dipstick readings on the 2.0 leave something to be desired, but that may also be related to the variable you're chasing.

Spitballing numbers... There are 144 fluid ounces in 4.5 quarts of oil. The excess measured in one instance was 4oz, 4/144=0.0278*100=2.78%. Fuel dilution is estimated at 1% so that leaves you with <2% extra volume to account for after you've acknowledged there could be a few teaspoons of coating still in the drain pan, after wiping up, and whatever may still remain saturated in the filter media. Have you also accounted for temperature? Oil expands when it is hot, and an example I found off the internet* expansion of 189ml on 3.5L of volume, or 189/3500=0.054*100=5.4%

Although probably not the most accurate, BS' fuel dilution test doesn't seem to indicate fuel dilution is a major problem, and still within spec, according to its methods. I kind of agree that this warrants more investigation, another testing method or another testing vendor, to confirm or rule it out.

Again, guessing here, but I wonder if the turbo's oil circuit is holding onto oil somehow. The dipstick timing issue along with the volume of oil that returns to the sump overnight isn't insignificant, which makes me think this circuit could be a factor.

Have you controlled in your experiments the timing at which you drain, i.e. "hot drain" (15 min after hot engine shutoff), or cold drain (engine sat overnight)?

You'd think you'd see the inverse, too, if the turbo circuit was holding oil, you'd also come up short on volume at times when draining.

I drain the oil when it's been sitting, probably against recommendations, but I am not seeing volume fluctuation. I completed my 5th oil change in 7500 miles yesterday, crazy, but it looks like this: Once at ~1,000 miles for break-in. Again at 2,000 after a trip to Moab. Once at 4500 before a Trip to Moab. Again at 5500 after a trip to Moab. And yesterday at 7,236 miles, after 2 months in the desert with extremely dusty conditions and a lot of hard driving.

 

[JLUR Farout]

All valid arguments. I tend to do my oil changes after the Jeep has sat overnight. Same with driveline fluid changes. I don't enjoy getting burned any longer. I am cautious with changes and try to capture as much as possible. Part of why the oil analysis shows what it does, is my fault. I would not let the oil level get too high before I would drain it off. Especially in the fall when it was really bad. Again, I have it all written down, which is what led the dealer to trust me. I am hoping their solution fixes it.

 

[JLUR Farout]

DEALER SAYS THE PROBLEM SHOULD BE FIXED.

Both fenders came off, catalytic converter comes off, engine coolant bottle gets moved out of the way, and some other things. Took several hours more than Mopar/FCA/Jeep/WTF knows what to call them says. I like the dealer I go to, I drive three hours to see them. I was/am the first 2.0L fuel pump replacement for the dealership.

Turns out after my visit in the fall, the service manager talked to the Jeep tech group people who travel to dealerships. One guy said he seen a situation like mine, same parameters and odd rates of oil growth, out on the east coast. The HPFP replacement fixed it. So, that is what they replaced yesterday.

Below are pictures of the old pump for any fellow nerds to geek out on.

 

[JLUR Farout]

My problem is back. I am gaining oil again. I've drained off one quart already, and now have gained 16 oz back gain. I'm going to drive it this next week, then do an oil change and OA.

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