A little gasoline in the diesel

[Aguabago]

5 gallons of petrol (gasoline) were added to my almost full 90 gallon diesel tank. So now there is a mixture with roughly 6% gasoline (petrol) and 94% diesel, and its full.

The engine is an older (2002) Ford 75 HP; no turbo charge and nothing fancy; just a basic diesel engine.

What to do ....

I've done some research. Conservative approaches are stop everything and pump everything out. Risks of lower lubrication; improper combustion timing, stuffing up the fuel pump, etc. But there is some info that if the mixture is a low enough percent of petrol that they were able to burn it off.

I am interested to hear if anyone has been in this situation and has successfully simply run through the fuel, perhaps frequently topping up the diesel to get the diesel percentage higher. And to hear if there were any longer term issues that came up from running the fuel through the engine.

[Pandor]

In older engines like yours, a lightly diluted (say 90% diesel/10% gasoline) mix will likely pass through with little to no detriment. It might simply cause reduced engine power, perhaps a bit more noise. I can’t say for newer emission tier engines.

I would simply follow your approach to top off more frequently for a bit.

[longjonsilver]

Is not diesel fuel conditioner a mix of 2 cycle oil and white gas? How different is gasoline from white gas? Sounds like a high percentage of gasoline tho. Perhaps put some 2 cycle oil in to lubricate the injector pump?
jon

[GRIT]

In Canada, in winter, eons ago; some folks used to add gasoline to their diesel. The addage was that up to 10% wouldn't do any harm.

I repaired diesels in heavy equipment for a number of years, and several of my customers were convinced of the benefits of adding gasoline to their fuel, in winter.

I don't advise you do it on purpose, but at 6%, in an engine of that vintage, you'll be fine.

As advised in another post, fill up more freqently for a while, so as to reduce the percentage of gasoline in the fuel.

Cheers.
Paul.

[Captain Bill]

A couple of years ago I had to dock a bit away from the fuel pump and the dock worker handed me the wrong handle. I got about three gallons in a 60 gallon tank before the smell hit me. I filled it to the top with diesel and went about my trip. 2002 old mechanical Yanmar and no ill effects at about 5% gasoline.

[UYA]

From https://en.m.wikipedia.org/wiki/Winter_diesel_fuel


For some diesel motors it is also possible to add even lighter fuels like gasoline to extend the CFPP characteristics. Some car makers were recommending adding up to 20% gasoline to permit operation in cold weather (at the price of higher consumption) and it had been common practice in Europe where No. 1 fuel is not offered at gas stations. Since the 1990s car makers began selling only direct injection diesel engines — these will not withstand any gasoline portions in the fuel as the high pressure in the injection device will not withstand any loss of lubrication from fuel oil without doing damage to the injectors. High pressure fuel pumps depend on diesel fuel for lubrication and the addition of gasoline will cause adverse wear and eventual failure of the pump.

[Paul L]

Since gasoline is lighter than diesel I assume it will float on top of the diesel if not stirred around. Maybe leave the fuel tank cap off, but covered from rain, when not using the boat and let some of the gasoline evaporate. Either way I don't think you would have much issue with that ratio of fuels as long as you aren't emptying the tank and the two have not mixed.

[DefinitelyMe]

You will experience no problems with burning it in the engine. You might actually find that it helps things overall since gasoline is a strong biocide and will help to clean up any bacterial growth. However it is very risky.

Diesel fuel in a tank is low-risk because the vapour pressure is very low. i.e. the mix of fuel to air in the vapour above the liquid fuel contains too little fuel to present an explosion risk.

Gasoline in a tank is low risk because the vapour pressure is very high. i.e. there is not enough oxygen to present an explosion risk.

Mix them together and the risk goes up. At a certain proportion there is the perfect ratio of fuel vapour to air in the vapour above the fuel to explode with the slightest spark. From memory, that 'optimum' mixture is about 5% gasoline.

So, gasoline in the diesel is not bad for the engine in small quantities (yes, it will result in reduced lubricity, which will wear out the injection pump a little faster, but I don't think it will be significant). It's common practice in the winter time in many countries. I've added gas myself when cruising in remote areas without access to proper biocides. But in that case we're talking about something like 0.1%.

You have a significant explosion risk. The safest thing would be to remove the fuel and replace it. If you decide not to do that, please at least try to mitigate the risk by keeping the tank full at all times, so that there isn't a huge volume of explosive vapour in your tank, by topping up with diesel every time you run the motor.

[jamhass]

If your primary concern is reduced lubrication, consider adding an appropriate diesel additive.

[Cadence]

Originally Posted by Aguabago

5 gallons of petrol (gasoline) were added to my almost full 90 gallon diesel tank. So now there is a mixture with roughly 6% gasoline (petrol) and 94% diesel, and its full.

The engine is an older (2002) Ford 75 HP; no turbo charge and nothing fancy; just a basic diesel engine.

What to do ....

I've done some research. Conservative approaches are stop everything and pump everything out. Risks of lower lubrication; improper combustion timing, stuffing up the fuel pump, etc. But there is some info that if the mixture is a low enough percent of petrol that they were able to burn it off.

I am interested to hear if anyone has been in this situation and has successfully simply run through the fuel, perhaps frequently topping up the diesel to get the diesel percentage higher. And to hear if there were any longer term issues that came up from running the fuel through the engine.

My concern would be they settle out separately and your pickup picks up pure gas/petrol. I've seen a rod through the side of a block.

[longjonsilver]

Originally Posted by Cadence

My concern would be they settle out separately and your pickup picks up pure gas/petrol. I've seen a rod through the side of a block.

Have you actually seen this or is this speculation? Since they are both nonpolar, they should be 100% soluble in each other. Diesel conditioner is basically 90% two cycle oil and white gas. Does the diesel conditioner ever separate from the diesel???

jon

[Halam]

I've filled my diesel car with pertrol a couple of times and it's been fine.

[zstine]

Nobody mentioned that Gas and Diesel engines run on different principles. Diesel engines auto-ignite via high compression ~20:1, while gasoline engines need a spark ignition and typically compress around 9:1. Gasoline auto-ignites at like 11:1 or 12:1 compression.

So, too much gas in a diesel engine will result in pre-detonation or pinging which can result in a quick death.. I would guess that if well mixed the OP will be okay since the concentration is low. BUT if it does settle out(?) then he could get into detonation and engine damage.


High octane will reduce pinging... It wouldn't hurt to add a few bottles of octane booster. And yes definitely some lubrication additive as others said.

I'd run it but listen carefully to the sound. Pinging is audible, I'd shut down right if you hear any.

[Cadence]

Originally Posted by longjonsilver

Have you actually seen this or is this speculation? Since they are both nonpolar, they should be 100% soluble in each other. Diesel conditioner is basically 90% two cycle oil and white gas. Does the diesel conditioner ever separate from the diesel???

jon

I've seen it. A neighbors daughter, 15, thought she was doing good to top off Mom's tank. Gas station may have been 1/2 a mile away. The woman came over and asked me to look and see what I thought. It was you need a new motor. The rod was right through the block.
I wouldn't bet on the gas and diesel becoming homogenous.
For what is worth?

[AJ_n_Audrey]

Years ago, in the Army in Korea during the winter when it got to 5 degrees F or so, we added about 10% gasoline to diesel generators. Never seemed to cause a problem, but that doesn't mean it is recommended. I suspect if you keep topping off with diesel you'll be fine.