Based on the G100UL fuel leak thread what's your position?

[A64Pilot]

8 hours ago, Pinecone said:

Except that Lycoming has already published a Service Bulletin that doubles the oil change interval when using unleaded fuels.

I think that double the oil change interval is a significant increase.

And once 100LL is gone, synthetic oils will further increase oil change intervals, as they did in auto.  We went from 3000 mile oil changer intervals to over 15,000 miles.

The primary driver in extended auto oil change intervals is the extraordinary clean burn they have plus very reduced blow-by and nearly zero oil burn, when was the last time you cleaned the carbon off your plugs in your car?

Auto engines come out if the box with near perfect tolerances now, they require no break in etc now because of that.

You just can’t draw comparisons with auto engines, unless you compare to ones built just after WWII.

Yes I’m aware of the doubling of oil change interval and I’m certain doing so the engine will still make it past warranty.

But we don’t I believe know what the Gami fuel will do to oil either

Edited January 18 by A64Pilot

[Justin Schmidt]

2 minutes ago, A64Pilot said:

The primary driver in extended auto oil change intervals is the extraordinary clean burn they have plus very reduced blow-by and nearly zero oil burn, when was the last time you cleaned the carbon off your plugs in your car?

Auto engines come out if the box with near perfect tolerances now, they require no break in etc now because of that.

You just can’t draw comparisons with auto engines, unless you compare to ones built just after WWII.

Yes I’m aware of the doubling of oil change interval and I’m certain doing so the engine will still make it past warranty.

Are we forgetting that auto manufacturers are still saying 6000 miles or 3 months

[GeeBee]

22 minutes ago, Justin Schmidt said:

Are we forgetting that auto manufacturers are still saying 6000 miles or 3 months

Not mine. Somewhere between 10 and 12K miles depending on the sensor or 1 year. Usually I time out before mileage.

[A64Pilot]

19 minutes ago, Justin Schmidt said:

Are we forgetting that auto manufacturers are still saying 6000 miles or 3 months

I don’t believe most do. way back in the 90’s or maybe earlier GM developed GMOLS or GM Oil Life System, it was an algorithm that started with some number and every cold start and other ops that was detrimental to oil life decremented some amount from the starting number, when it hit zero or near it anyway you were notified your oil needed changing.

They won several awards and I believe if it was Patented that has run out and most manufacturers followed suit

My personal take is oil is at its best when you pour it from the bottle, from there it degrades, extending oil change intervals is a fools game.  Auto manufacturers determine how bad it gets before it’s no longer doing the job, often marketing drives that number. For example back about 2010 or so the Prius had a 5,000 mile recommended oil change interval, and many environmentalists were slamming Toyota why if it was truly a “green” car wasn’t its oil change interval longer, so Toyota gave in and doubled it, either way it would easily get to the end of warranty. This from the company that had just gotten through the infamous sludge lawsuits.

But, I don’t see any of the couple of manufacturers of Aviation oil developing new Syn oils when UL fuel becomes the norm. I think the market is too small for the payback, and the Mobil-1  issue is too fresh.

I’ve always wondered why Exxon pulled out, I thought Elite was excellent from what I could tell. My belief is the small profit didn’t offset the liability.

Edited January 18 by A64Pilot

[Justin Schmidt]

3 minutes ago, A64Pilot said:

way back in the 90’s or maybe earlier GM developed GMOLS or GM Oil Life System

I have seen that code, has nothing to do with actual oil life. It's actually really laughable what they do. Same of all "oil life monitors"

Gm manuals still say 6000. Hyundai up to a few years ago said 3 "rough" 6 otherwise.

Ultimately, it depends on condition. How you drive, type oil, environment etc. only oil analysis and bore scope will tell. Same for our planes. 

[Gary0747]

I am late to this discussion but wanted to throw in a couple of comments   I attended the presentation in Buckeye last year and asked the question about what testing had been done on our polysulfide fuel tank sealants.   I just got a cursory answer that it was currently in an airplane fuel tank with no signs of leaks.  I would like to see testing that might predict the long term effects on these sealants.   Perhaps measuring surface hardness readings or adhesion force measurements both over exposure time.  
Any new fuel that replaces lead and straight chain hydrocarbons with aromatic hydrocarbons like toluene, benzene, xylene, etc to maintain octane will be more aggressive on paint and sealants and some types of rubber.   The aromatics will typically increase the octane lost by removing the lead, but should have initially raised red warning flags in the development of this or any new fuel.   I would have thought it critical to test the long term compatibility effects on day one of any new fuel development project like this.  
I think polyurethane paints and sealants will better resist aromatic chemical attack than acrylic paints and polysulfide sealants  

[A64Pilot]

10 hours ago, Justin Schmidt said:

I have seen that code, has nothing to do with actual oil life. It's actually really laughable what they do. Same of all "oil life monitors"

Gm manuals still say 6000. Hyundai up to a few years ago said 3 "rough" 6 otherwise.

Ultimately, it depends on condition. How you drive, type oil, environment etc. only oil analysis and bore scope will tell. Same for our planes. 

I think (my opinion) for most it’s pretty good, and (close enough). Average Joe and Jane don’t have a clue and don’t want to either, they appreciate a light that comes on and says change oil.

A lot has to do with expected life of the engine, if you accept say that if the engine lasts 100,000 miles then the automobile is at its end of life, then it’s likely even with extended intervals that you can get 100K out of a motor.

Here is the other thing, if you read most manuals at least all of my vehicles I was always in the (extreme use) or whatever name they tagged it with, you know trailer towing, highway driving, frequent short trips, etc etc. then you were to use a set mileage number, in some cases that’s as low as 3,000 miles.

Milage is not really a very accurate way to schedule oil life, but it was forever the only thing available, hours is better, but even more accurate is the amount of fuel used, fuel use rate being a good metric to determine how hard the engine was being run.

But to continue the drift, I had a 2010 Prius that came with a 5,000 mile OCI, that Toyota under pressure changed to 10,000 miles. I changed it at 5,000 miles using Mobil 1 0W-20 oil, I got rid of it at 285,000 miles because the car interior etc was just worn out, the engine consumed no oil. Before people say it was babied, it’s last four years it was my Daughters College car and she ran it hard, I had to put four new rotors on it and pads because she had warped all four, so she was abusing the little car. I suspect at 10K OCI that engine wouldn’t have made it, but still would have gone past 100K.

Sorry it was 270,000 miles, 285K was an Old Mercedes 220 I had decades ago, it died in an accident.

 

Edited January 18 by A64Pilot

[Schllc]

1 hour ago, A64Pilot said:

I think (my opinion) for most it’s pretty good, and (close enough). Average Joe and Jane don’t have a clue and don’t want to either, they appreciate a light that comes on and says change oil.

A lot has to do with expected life of the engine, if you accept say that if the engine lasts 100,000 miles then the automobile is at its end of life, then it’s likely even with extended intervals that you can get 100K out of a motor.

Here is the other thing, if you read most manuals at least all of my vehicles I was always in the (extreme use) or whatever name they tagged it with, you know trailer towing, highway driving, frequent short trips, etc etc. then you were to use a set mileage number, in some cases that’s as low as 3,000 miles.

Milage is not really a very accurate way to schedule oil life, but it was forever the only thing available, hours is better, but even more accurate is the amount of fuel used, fuel use rate being a good metric to determine how hard the engine was being run.

But to continue the drift, I had a 2010 Prius that came with a 5,000 mile OCI, that Toyota under pressure changed to 10,000 miles. I changed it at 5,000 miles using Mobil 1 0W-20 oil, I got rid of it at 285,000 miles because the car interior etc was just worn out, the engine consumed no oil. Before people say it was babied, it’s last four years it was my Daughters College car and she ran it hard, I had to put four new rotors on it and pads because she had warped all four, so she was abusing the little car. I suspect at 10K OCI that engine wouldn’t have made it, but still would have gone past 100K.

Sorry it was 270,000 miles, 285K was an Old Mercedes 220 I had decades ago, it died in an accident.

 

 

My uncle, in the early 80’s, participated in a synthetic oil change study where he sent samples of his oil every 1000 miles for analysis. He did this for three years. 
As a result of this, he told me changing a cars oil every 15-20k was more than adequate. 
Since then I have had at least a dozen trucks go past 300k, two past 500k, and at least a dozen more past 200k, using these intervals with full synthetic.  
None of these engines failed either, I just traded or sold them and they were all running strong.  
I currently have two Toyota land cruisers with north of 200k using these same intervals, and I have no intention of changing them for newer cars any time soon. 
I have never had to do any engine work besides plugs, alternators, coils, and a front or rear main seal here and there. 
The average Americans vehicles do not drive in water, sand, or conditions daily that would require these more frequent intervals, and while there is no downside to changing more frequently, it is in my opinion unnecessary. 
my airplanes engine is obviously very different. I can see the speed in which the oil is filled with contaminants, with a turbo air cooled airplane engine, I change the oil every 20-30 hours. 

[A64Pilot]

@Schllc 

I think, in my opinion the most relevant part of your post is where you state and I’m paraphrasing that our aircraft engines don’t really have many similarities to Automobiles, and I agree.

Maybe we could draw some correlations to our Grandfathers cars, but modern automobiles are very advanced marvels of technology by comparison. They have achieved things that I thought simply not possible

 

[gabez]

Quick update: I was able to see my plane, the tanks, videos of the borescope of the cylinders. I was also able to see the cylinder, piston and push rod of the Grumman that nuked at Hollister. Because it's an active FAA investigation I am told to wait to post pics/videos until the FAA makes their decision as this is with DC now. Investigators came took pics, samples and actually put G100UL back into my plane and run it to collect oil sample...oof. To GAMI's defense they can't access samples either as per FAA request. 

The leaks are coming from the copilot aux tank, outboard seam and inboard seam. Also from 3 screws from an access panel on the pilot side main. The sealant is original from when Mooney built the aircraft and when the Aux tank were installed. On the outboard side it seems the fuel drains off the tank from a drain hole. Again, this aircraft did not have leaks and the magnitude of the current leak is pretty vast. I would have had blue stains of the same magnitude. Plane just completed annual in November we would have seen this if it was there. 

I used about 80 gallons of G100UL, 30 gallons, 30 gallons, 20 gallons, give or take:

Refuel/Flight 1: 15 gallons in the Laux, 15 gallons in Raux, main(s) had about 20 gallons each of 100LL

Refuel/Flight 2: 15 gallons in the Laux, 15 gallons in Raux, main(s) had a mix of 100LL/G100UL

Refuel/Flight 3: 10 gallons in the Laux, 10 gallons in Raux, main(s) had a mostly if not all G100UL 

So the aux saw most of the G100UL and the main only at the very tail end. The RV and Grumman had the G100UL for several weeks before the former realized fuel on the floor and the Grumman 

Repairs have started already. I am also told some aircraft that had purchased G100UL, have now pulled the fuel out of their tanks so I don't believe many are purchasing the fuel (the latter is just my hypothesis). 

Additionally, the paint peeled from the inside out like it exploded I think pouring fuel over the paint does not reflect the dynamic of what is happening. Independently from any lab tests, what we are experiencing is as simple as, the tests performed were not representative of real world conditions and that is to nobody's fault, it happens with car manufacturers all the time, GAMI needs to step in now and make it right financially. 

Also, I keep hearing of testing about paint and O rings (which is great) but any testing on sealant? I agree with GAMI fuel belongs in the tanks....we can't keep it there tho so I want to see what testing what done on the tank sealant. 

 

More to come...

Edited January 18 by gabez

[GeeBee]

Has anyone done a DHA of the fuel out of the pump at KRHV and KWVI? I would be interested in comparing those results to the DHA when it left the loading facility.

[gabez]

11 minutes ago, GeeBee said:

Has anyone done a DHA of the fuel out of the pump at KRHV and KWVI? I would be interested in comparing those results to the DHA when it left the loading facility.

When I reached out to VITOL the answer was "work closely with GAMI"

[Marc_B]

19 minutes ago, GeeBee said:

Has anyone done a DHA of the fuel out of the pump at KRHV and KWVI? I would be interested in comparing those results to the DHA when it left the loading facility.

I suspect that GAMI has, and would be shocked if they had not.  If this was truly an issue GAMI has never seen with G100UL, first and foremost would be to r/o contamination either accidental or intentional.  This would be easy to take a sample from the pump, take a sample from all aircraft with issue, and compare with originating batch.  Part of the spec with G100UL is performing a DHA from each batch of fuel to report that it is conforming and to establish the "fingerprint."

[gabez]

The stains left on my tie down from G100 2 from each sump valve, when I sump the fuel for water and then dump it. The one in the middle when I pull the ring from the gasclolator. 

[gabez]

they forgot the other planes, RV, 421, M20F, M20Encore .

Edited January 19 by gabez

[redbaron1982]

1 hour ago, gabez said:

they forgot the other planes, RV, 421, M20F, M20Encore .

I've updated Wikipedia's AvGas article to mention the concerns around material compatibility 

[Aaviationist]

So you want gami to pay you to reseal the tanks that have never been resealed in what…. At least 50 years?

it is not possible this aircraft didn’t have tank maintenance deficiencies prior to using 100ul and I do not believe it’s possible for 100ul to eat through a properly maintained tank like that in the time frame you specified. 
 

to be honest, the comment of “gami making it right financially” doesn’t really make any sense. 
 

No Mooney that old with the original tank sealant A:doesn’t leak somewhere and B:is recommended to be resealed. 
 

Also, I’m sure it’s illegal in your area to dump fuel onto the ground. 

[Echo]

Just because someone does not believe something to be true does not make it so.

[McMooney]

On 1/18/2025 at 7:36 AM, A64Pilot said:

I think (my opinion) for most it’s pretty good, and (close enough). Average Joe and Jane don’t have a clue and don’t want to either, they appreciate a light that comes on and says change oil.

A lot has to do with expected life of the engine, if you accept say that if the engine lasts 100,000 miles then the automobile is at its end of life, then it’s likely even with extended intervals that you can get 100K out of a motor.

Here is the other thing, if you read most manuals at least all of my vehicles I was always in the (extreme use) or whatever name they tagged it with, you know trailer towing, highway driving, frequent short trips, etc etc. then you were to use a set mileage number, in some cases that’s as low as 3,000 miles.

Milage is not really a very accurate way to schedule oil life, but it was forever the only thing available, hours is better, but even more accurate is the amount of fuel used, fuel use rate being a good metric to determine how hard the engine was being run.

But to continue the drift, I had a 2010 Prius that came with a 5,000 mile OCI, that Toyota under pressure changed to 10,000 miles. I changed it at 5,000 miles using Mobil 1 0W-20 oil, I got rid of it at 285,000 miles because the car interior etc was just worn out, the engine consumed no oil. Before people say it was babied, it’s last four years it was my Daughters College car and she ran it hard, I had to put four new rotors on it and pads because she had warped all four, so she was abusing the little car. I suspect at 10K OCI that engine wouldn’t have made it, but still would have gone past 100K.

Sorry it was 270,000 miles, 285K was an Old Mercedes 220 I had decades ago, it died in an accident.

 

all my cars manuals read something to the affect of change the oil when the light comes on, atleast once per year.

camaro, jeep and jaguar, actually the jag says every 12000 miles or something like that.

my experience, modern automobile engines are fine at 100k, it's everything else that's starting to wear.  suspensions, brakes, etc, interior finishes.   Except for oil changes and tire rotations, i haven't had to have a car serviced in the last 20 years.   actually that's a lie, lost the ignition coils on an older camaro at something like 125000 miles.

[Marc_B]

If it was one aircraft out of 100,000 you could suppose it was just mere coincidence.  I think having at least 7 aircraft with paint damage that spans at least 5 manufacturers with a hundred or so aircraft that were fueled...that's more than coincidence and deserves a thorough and close look to determine the cause.  It might not be G100UL, but it certainly might be as well.  The fact that an A&P (FAA certification, real person) was able to recreate the apparent damage using G100UL is not definitive proof but is undeniable that this isn't something that can be ignored as "not an issue with our product."  Remember, Luvara is FAA certified and would probably loose his license if found to be maliciously tampering with evidence (at a minimum).

GAMI posting YouTube videos only showing Beechcraft louvred access panels for every single "test" that they ran...that's not scientific, isn't very credible for a company that wants to have 100% of the market share of 100LL, and doesn't pass muster as "hard data".  The statements that Mr. Braly has made here are very generalized "Hard proof that 100LL nor G100UL cause paint damage."  Or pointing to 100LL with 29% Toulene on a single sample over a decade ago and saying that is what damages elastomers...

Perhaps GAMI is investigating this behind the scenes and actually has a thorough crew of investigators from GAMI and the FAA (I sincerely hope this is the case)?  But GAMI's posts on the social media outlet of Mooneyspace, BeechTalk, BackCountry Pilot, etc are so far not more than an attempt at social influencing, advertising, and damage control.

If a fuel is advertised to be 100% drop in without any modification but then requires new sealant (specific new fuel resistant type) and new paint (specific new fuel resistant finish and prep), new fuel lines, and new o-rings...that's not 100% drop in as is.  It's drop in with an asterisk and requires definition on an ICA/STC paperwork...(either that or perhaps an AD in the future).

The fleet is a phase two of a "beta test" to uncover where issues are seen.  But you have to believe the issues and adapt or else you're stuck with version 1.0.0 forever.  If that's the case, this may not be a fleet wide fuel.

[Marc_B]

7 hours ago, Aaviationist said:

So you want gami to pay you to reseal the tanks that have never been resealed in what…. At least 50 years?

This is exactly the reason that you find disclaimers on products everywhere.  If you didn't say "use caution with wet wings as this may accelerate leaks and lead to paint damage" and instead said "will be invisible to your aircraft or engine compared to 100LL"...you might have a civil problem.

Heck, they have disclaimers not to allow babies to play with plastic bags.

But keep in mind, NONE of this is already decided and no one has clearly defined where liability coverage is found with G100UL.  Until we actually have actual hard scientific data it's limited observational data with LOTS of speculation all the way around.

[gabez]

I went and see the RV at KWVI. the plane is from 2007, the pilot side tank dumped fuel into the cockpit and down the belly of the plane. paint was damaged and some pieces of paint were on the floor. wet wings.

[A64Pilot]

1 hour ago, Aaviationist said:

So you want gami to pay you to reseal the tanks that have never been resealed in what…. At least 50 years?

If it’s ever proven that they are at fault, yes. I believe Mobil did for the oil problem regardless of engine age?

However I believe the owner is a Lawyer, so surely he’s covered pretty well.

Way I see it as a Layperson, is that there really is a compatibility problem, or it’s one heck of a coincidence. I have no way of knowing which it is, but I believe two things.

1. If I was using it or even used it once, I would have that documented by every means that I could starting with receipts and if I lost it, because I have never kept receipts I’d ask for one

2. I’d not use it until the issue, if there even is one is solved.

Personally I’d never use it because we are certain that it reacts negatively with Nitrile, and my fuel bladders are apparently made from Nitrile.

Everyone keeps saying O-rings, and they are not that big a deal, but they may be the canary in the coal mine. The bigger deal is fuel pumps, fuel flow transducers, pressure transducers, fuel servo, fuel spider on top of the engine, who knows what else, there are plastics and rubber throughout the fuel system, heck even the fuel quantity transmitter floats and they probably have seals too.

O-rings aren’t really the issue because in most all cases they aren’t really that exposed, they are in grooves that when the part is assembled there is very little in contact with the liquid, but seals etc are exposed and I don’t know where Viton replacements can be sourced for those components I listed above.

But then, maybe this will all turn out to be a non issue.

Having worked a lot with the FAA myself I know their overriding concern is “can this reflect negatively on me?” I’m actually surprised that they haven’t stopped the sale of the fuel until the investigation is completed myself, the fact that they haven’t indicates something I think, what that is I’m uncertain

Edited January 19 by A64Pilot

[GeeBee]

37 minutes ago, gabez said:

I went and see the RV at KWVI. the plane is from 2007, the pilot side tank dumped fuel into the cockpit and down the belly of the plane. paint was damaged and some pieces of paint were on the floor. wet wings.

What did the builder use to seal the tanks?

[MikeOH]

28 minutes ago, GeeBee said:

What did the builder use to seal the tanks?

Something impervious to 100LL