Unleaded gas in diesel tank

A very silly mistake! last week while filling up my "day tank", one of my "helpers" handed me the gasoline nozzle rather than the diesel nozzle. I pumped in about 20gals of gas before i realized the mistake. I then decide to fill up the tank with 300gals of diesel. My questions to the forum is, is this going to cause major problems with the engine/fuel system/injectors? I have added a gallon or so of optilube (far more than the manufacturers required amount) as a fuel additive and diesel lubricant. I have taken out the boat twice since this incident and have not noticed any issues. My options are: a) move all the contaminated fuel to one of my reserve tanks (I have three reserve tanks) using my polishing system; b) refill the day tank with new fuel; find an outfit to pump out the contaminated fuel (have no idea how they will do this); c) further dilute the contaminated fuel with clean fuel from other two reserve tanks (capacity 800 gals) and then move it back to the day tank.
What does the combined wisdom of the forum say?

Call the engine manufacturer. If it were my diesels I'd not run them and throw the contaminated fuel away. Injectors and fuel delivery pump are areas of concern. Sounds like you have about 150 hours of fuel in that tank, that's a lot. John Deere 6068?

The engine is an IVECO Nef. There is one rep here on the West Coast, not very responsive. But thanks for the suggestion, i will reach out to them.

I don't think 6% gasoline mixed with diesel is going to be a problem, particularly with a bunch of diesel lubricant thrown in.

Is it an older mechanical injection engine or a modern, common rail system. I would be a little more worried about the latter but not much.

Diesel has a boiling range spec and that spec allows a certain amount of lighter gasoline type components in the fuel as long as it meets the lubricity and cetane spec. Just don't know how much or what would be the harm if it were exceeded. But like I say my gut is that it will be fine.

Let's see what Ski says.

David

I agree with David of its an older mechanical engine.
The old VW diesels allowed 25% gas in the winter. That was in the owner's manual.
I'd dilute as much as you can by moving some of it around if you can.

azubair said:

The engine is an IVECO Nef. There is one rep here on the West Coast, not very responsive. But thanks for the suggestion, i will reach out to them.

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Though it would have been better to have isolated the RUG right when it happened,
that ship has sailed.

You have already run on this mixture so any accelerated wear has occured by now.

I would distribute and dilute the mixture by polishing and transferring and top it up.

DavidM: it is a common rail system.

jleonard: "I'd dilute as much as you can by moving some of it around if you can.". That is my plan. I will dilute it with almost 800gals of diesel. A slow process because my fuel transfer pump is slow. And keep adding the fuel additive/lubricant/cetane booster

KnotYet: "Though it would have been better to have isolated the RUG right when it happened".
The issue at the time was: how to get the gasoline out of the day tank!

I think that if the polishing system is hooked up to the day tank he might have been able to pump it into a small tank and get rid of it before adding the extra diesel. Too late now though.

What does the combined wisdom of the forum say?

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I guess the most important lesson here is the knowledge that most times "helpers" don't help that much.

jleonard said:

I guess the most important lesson here is the knowledge that most times "helpers" don't help that much.

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Correct. Now for a bit more non help. Today's gasolines have several additives that do not sit well. Meaning ethanol and MBTK. Ethanol's ability to attract water and create issues with sludge, rubber fittings and FRP tanks are well documented. Twenty gallons of gas containing up to 2 gallons of ethanol is an interesting bit of conjecture.

I would ABSOLUTELY empty the tank. There's folks that do this, and dispose of the contaminated fuel...... yes, it will be expensive, but so is a diesel engine.



And I'd call the manufacturer to see what I could do about the "already happened" damage. NOT GOOD. You may be able to skate on this one, but I'd be nervous without a check of the injectors and perhaps other components.



This is another case of just doing one's one fuel and being very careful about it. The only way I'd engage a helper, is after I've started pumping and I knew I would be back before filling, so I'd avoid any spills.

My worry would be that the gas and diesel do not "mix," but being different weights the gas may be separated from the diesel and get drawn to the engine as nearer pure gas. Like how water and gas don't fully mix.

Never mixed gas snd diesel. Do they mix and stay mixed. Or guessing would one sit on top of the other? Anyone know?

I agree with SeeVee, empty the tank before you run the engine again. And call the engine manufacturer to find out what may have happened and what you should do.

menzies said:

My worry would be that the gas and diesel do not "mix," but being different weights the gas may be separated from the diesel and get drawn to the engine as nearer pure gas. Like how water and gas don't fully mix.

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Soo-Valley said:

Never mixed gas snd diesel. Do they mix and stay mixed. Or guessing would one sit on top of the other? Anyone know?

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I'm reasonably sure they mix. I used to run a boat with a Cat D379. In the operator's manual was the approved cold weather starting with a mix of 10% gasoline and 90% diesel. And the caution not to run it that way, just get it started then switch to 100% diesel.

The other way to look at it is they are both petroleum products. Much like mixing lube oil and diesel or two cycle oil and gasoline. Not at all like mixing water and a petroleum product.

It depends on the design of the high pressure common rail pump. Likely this is a Bosch unit where the guts of the pump are lubed with fuel, then the fuel gets pumped to the injectors. If the fuel has low lubricity, the guts of the pump can wear, THEN the wear products go and foul the injectors. Actually a crappy design. The injected fuel should not come from the area where wear could be occurring. This has been a problem on other Bosch HPCR's (VW, some trucks), but not so much on other Bosch systems. I am not a student of which pumps are sensitive and which ones are not so much.

6% gas is going to reduce the lubricity of the fuel. But not that much. There is a lot of variation in the lubricity of diesel from various sources, and that natural variation is probably way more than 6%. And the 6% gas might (or might not) reduce the lubricity by the same 6%. That's getting into PhD level tribology, and I ain't one!!

I would probably dump a couple of gallons of outboard two-stroke TCW3 oil (ashless for burning) in the tank. That will raise the lubricity of your mix about as much as the gas reduced it. It also tends to mix well without agitation.

I would not worry about the gas not mixing with the diesel. Adding 300gal to the mix would mix it just fine.

The additive you put in will raise lubricity too, just not sure how much.

Then run the engine, but not at high power. The loads on the HPFP pump are greatly increased at high power (computer raises rail pressure, pumping loads go way up). So at lower loads the lubricity is less critical.

I had someone do this and asked me to pump out his tank. I told him it was not necessary, but he insisted. So I pumped it into barrels and transported to my shop. Over the next year I burned it in my boat and car and had zero issues. I did put some outboard oil in.

Great advice Ski. It confirms my gut reaction. Lube it up with two cycle oil and you should be fine.

David

IIRC, from a lawsuit in which I represented a fuel supplier, one of the issues was mixing different fuels in the local station's in the ground tanks, so thousands of gallons. There was a % mix that was considered tolerable. Call a refinery, big fuel supplier, pipeline operator...anyone who might know that % for gas in diesel for that answer.

I'm in the drain and filter group.
Nobody has any worries about lifting the head if a shot of gas gets injected ??

No worries about "lifting the head". A shot of diesel has more energy than gas, and the fuel is injected over time so no chance of pre-ignition or detonation.

on 20 gallons gas in the 300 gallon diesel tank, that`s only about 6% gas! i`ve mixed the same thing, was no way to clean it out, so i just ran it till it was down, then added more diesel to dilute it! should`nt be a problem...clyde

I would follow Ski's advice.
However, and hindsight is always 20/20, I would not have added more diesel fuel after discovering the "gas mistake", I would have had it pumped out at that point (if it was possible).
Another example of how we all have to be soooo careful at the fuel barge to ensure that the "right stuff" goes into the "right tank". Mistakes can happen way too easily.

I will chime in here. Years ago I was watching a pretty girl and grabbing the nozzel to fuel my Dodge diesel pickup. Well, the truck ceased running when I reached my driveway. At the time I was about 80% gasoline and 20% diesel in a Cummins 6BT.
I removed as much fuel as I could siphon from the tank, about 90%. I reloaded with diesel primed the fuel filter with diesel and drove that truck about another 80,000 miles without difficulty. I suspect that you will be okay with running the balance of your fuel. I wouldn't run it WOT for no other reason than "just because".

The question is a classic risk reward. I prefer to eliminate risk when the amount to be spent is far less money than the potential risk. Engine damage and fire concerns are not appealing to me.

Disposing of about 400 gallons of diesel should not be that expensive. Once in drums there are about 10 TF members that will gladly take it from the OP and transfer into their vehicles or boats. Some of these potential users are quite close.

Ideally, stop filling the tank. Throw some valves to use an uncontaminated tank until you figure out the danger/damage potential.

Personally, I'd have paid to have the tank emptied and polished, if that would work, or pay disposal fee.

However, with Ski's input and personal experience, I'd now follow his advice.

In my 60s now, I have a saying, "you're never too old to do stupid stuff". I still do.

If it were me, I would :

Put some lubricant in it
run it,
refill often (don’t let tank run down)

And

Faggettaboutit!!!!

If you are going to run it, I would at least dilute it as much as you could with the other tanks.

This was posted a while back but...

The same thing happened to me in the Bahamas once. A few minutes into pumping the dock hand guy yelled "stop the pump!." He gave me the gas hose instead of diesel and of course, being the Bahamas, they had green hoses connected to both pumps. I ended up with about 20 gallons of gas in my 670 gallon tank. I filled her to the top with diesel and ran it through and you would never have known it was in there. People in northern climates used to mix gas with their diesel in the winters all the time to thin it some. I did't have any lubricant additives since I was traveling over there when it happened to me but adding lubricant certainly seems like a good idea if you have some.

The question is being glossed over IMHO. Assuming the unleaded gas is 10% ethanol combined, with a newer design engine and with likely two years plus of fuel onboard there is no upside.

Sure, I remember the good old days when gasoline was used as a diesel thinner for old or wrong season diesel fuel. Been there done that. That was yesterday's fuel and old engines. The OP has options. One is to listen to those of us who have no skin in the game, another is to assume risk with fingers crossed or lastly give the fuel away.

With the Canadian border closed, storing onboard and consuming the fuel over multi years of Puget Sound cruising seems an unattractive option.

Ski in NC said:

No worries about "lifting the head". A shot of diesel has more energy than gas, and the fuel is injected over time so no chance of pre-ignition or detonation.

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In a diesel engine fuel is not injected UNTIL it is supposed to burn, so pre-ignition is impossible.

Gas is formulated to raise the octane, which is the measure of fuels resistance to pre-ignition.

Also as Ski in NC said diesel has more energy by volume.

Three reasons pre-ignition is not a problem.

I always wondered if the higher octane of gas would raise the flash point of the diesel fuel enough to make the starting harder.