1.5% fuel found in oil.

[Olivia2023]

Hello,

I have a 2023 Gladiator Mojave with 33k miles on it. I had the oil changed at 3k, and then religiously every 5k since. I send a sample of the oil into Blackstone Laboratories to get tested each time and all has been perfect up until this last oil change at 33k. Their report read: "Some fuel turned up this time, but just 1.5% (based on the flashpoint reading), which is harmless and probably from idling or another operational factor. Fuel didn't even thing the viscosity below spec. No other contamination was found, and wear metals are stable, so the oil worked well to limit wear at internal parts. This engine's looking really good!"

Talking with some of my mechanically inclined buddies (I am not), I have heard everything from "don't worry about it" to something about the fuel injectors may have an issue. I have no clue and am reaching out to the Jeep community for some opinions.

I spoke with the service manager and mentioned that since it was still under the factory warranty, I would like to have them take a look at it and give me their thoughts. The service manager was very good about it and offered to have me bring it in this next week so they could take a look at it. Any thoughts on this would be appreciated.

Be safe,

Steven Snow
Warsaw, MO

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[ShadowsPapa]

Did you drive it a minimum of 30 minutes before pulling the sample? (and not letting it idle before pulling the sample)?
On mine it takes a very long time to really warm the oil enough to drive out fuel contamination.

Short drives, like under 30 minutes at a time, are not good for gas engines. Fuel and moisture aren't driven out well.

if the fuel injectors "have an issue", then your O2 sensors will tell the PCM it's rich and it will attempt a correction - it would have to be bad enough it couldn't compensate.
If the O2 sensors read normal, it's likely ok.
You can't run too rich and not have signs in the system.

From my prior JT at 7,100 miles -

 

[Olivia2023]

Did you drive it a minimum of 30 minutes before pulling the sample? (and not letting it idle before pulling the sample)?
On mine it takes a very long time to really warm the oil enough to drive out fuel contamination.

Short drives, like under 30 minutes at a time, are not good for gas engines. Fuel and moisture aren't driven out well.

if the fuel injectors "have an issue", then your O2 sensors will tell the PCM it's rich and it will attempt a correction - it would have to be bad enough it couldn't compensate.
If the O2 sensors read normal, it's likely ok.
You can't run too rich and not have signs in the system.

From my prior JT at 7,100 miles -

On the driving - yes, the dealership is probably a 40 min. drive away, and they got it in quickly for the oil change. The truck rarely, if ever, sits and ideals. My primary question is "why the change" as the previous oil analysis have been under the same exact circumstances. Thanks for your reply, friend and I love the color of your Mojave. That wasn't offered when we purchased ours in 2023 and we got the sarge green. My entire world would be green if I had anything to do with it, and although I do like the sarge green - I might have opted for your choice had it been offered at the time!

 

[Watrmel0nBandit]

I wouldn’t worry about it if I was you.
The lab that you chose to test your oil doesn’t actually test for fuel dilution. This is a notorious issue when using Blackstone oil analysis services. They estimate that number based on other factors. I suggest using an accredited laboratory that uses a gas chromatograph to give you actual fuel dilution data if it’s a concern.

 

[DylanM]

Regardless of whether the fuel dilution was inferred or measured directly, the percentage was below a level to cause concern. Sounds like all of the other data points on the report support that it's not of any concern. Don't worry about it.

 

[ShadowsPapa]

I also wouldn't sweat it at this point. If they'll take a look at it, the readings they can gather in seconds on what the O2 sensors are telling them will either be in range, or out of normal range.

It's not alarming in any case.

 

[antihero]

I spoke with the service manager and mentioned that since it was still under the factory warranty, I would like to have them take a look at it and give me their thoughts. The service manager was very good about it and offered to have me bring it in this next week so they could take a look at it. Any thoughts on this would be appreciated.

What they're gonna do is have your vehicle sit there just to appease you because there's nothing actually wrong with it and there's zero reason to send in oil samples with every oil change.

 

[Gatorized]

Did you take the oil sample after you changed the oil or did you get a sample handed to you from someone else who did the oil change? Hard to tell if there was contamination in the drain pan or not… unrelated to the oil that came out of your engine.

 

[Hootbro]

I spoke with the service manager and mentioned that since it was still under the factory warranty, I would like to have them take a look at it and give me their thoughts. The service manager was very good about it and offered to have me bring it in this next week so they could take a look at it. Any thoughts on this would be appreciated.

They gonna charge you to look at it? Most dealership will not take direct action based on a customer supplied oil analysis unless other evidence presents itself as a possible warranty issue.

I will say I have probably 10+ Blackstone oil analysis done over the years on my multiple JT's and one JL with the 3.6L and none of them went over 0.5% for fuel dilutions.

As @Watrmel0nBandit mentioned, Blackstone's analysis for fuel dilution is just big fat guess mainly on flashpoint results. I recently did my first oil analysis on my new 2025 JT and set a sample to both Blackstone and oil Analyzers and what surprised me was Blackstone came back with the usual 0.5% for fuel dilution but Oil Analyzers said 1.3% which was more.

https://www.jeepgladiatorforum.com/forum/threads/2025-gladiator-3-6l-oil-analysis.94589/

Like mentioned, still below the 2% threshold that any more would be caused for concern, but I would have another lab next time check the oil sample to get a better feel on what is going on in terms of actual fuel dilution.

 

[ShadowsPapa]

and there's zero reason to send in oil samples with every oil change.

Every time is a bit much......
I do occasionally, especially early on, to establish a baseline, then every so often to watch trends, but not every change. Maybe every-other or every third.

 

[Deleted member 52902]

Dealer will be happy to charge you for this checkout. I mean, I do not think warranty will apply unless something is actually faulty and expressly covered.

Just saying, you might want to prepare for a healthy charge for X hour(s). Hope not of course.

 

[ShadowsPapa]

Dealer will be happy to charge you for this checkout. I mean, I do not think warranty will apply unless something is actually faulty and expressly covered.

Just saying, you might want to prepare for a healthy charge for X hour(s). Hope not of course.

Maybe they'll be lucky.....a service advisor spent 45 minutes with me on my jt for HVAC and other issues when I had the plow on it, no charge.
Maybe ..
Many aren't so kind

 

[40x40]

Did you drive it a minimum of 30 minutes before pulling the sample? (and not letting it idle before pulling the sample)?
On mine it takes a very long time to really warm the oil enough to drive out fuel contamination.

Short drives, like under 30 minutes at a time, are not good for gas engines. Fuel and moisture aren't driven out well.

if the fuel injectors "have an issue", then your O2 sensors will tell the PCM it's rich and it will attempt a correction - it would have to be bad enough it couldn't compensate.
If the O2 sensors read normal, it's likely ok.
You can't run too rich and not have signs in the system.

From my prior JT at 7,100 miles -

hey Bill, OP references "fuel" but not gas or diesel. both engines use injectors as his buddies refer to. what if this is a diesel and not gas?

 

[ShadowsPapa]

hey Bill, OP references "fuel" but not gas or diesel. both engines use injectors as his buddies refer to. what if this is a diesel and not gas?

It's a Mojave..........

 

[Sandman 4x4]

Did you drive it a minimum of 30 minutes before pulling the sample? (and not letting it idle before pulling the sample)?
On mine it takes a very long time to really warm the oil enough to drive out fuel contamination.

Short drives, like under 30 minutes at a time, are not good for gas engines. Fuel and moisture aren't driven out well.

if the fuel injectors "have an issue", then your O2 sensors will tell the PCM it's rich and it will attempt a correction - it would have to be bad enough it couldn't compensate.
If the O2 sensors read normal, it's likely ok.
You can't run too rich and not have signs in the system.

From my prior JT at 7,100 miles -

[/QUOT

Did you drive it a minimum of 30 minutes before pulling the sample? (and not letting it idle before pulling the sample)?
On mine it takes a very long time to really warm the oil enough to drive out fuel contamination.

Short drives, like under 30 minutes at a time, are not good for gas engines. Fuel and moisture aren't driven out well.

if the fuel injectors "have an issue", then your O2 sensors will tell the PCM it's rich and it will attempt a correction - it would have to be bad enough it couldn't compensate.
If the O2 sensors read normal, it's likely ok.
You can't run too rich and not have signs in the system.

From my prior JT at 7,100 miles -

All very good points to pass on.

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