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diesel & adding some old gas

Posted by homebound (My Page) on
Fri, Jan 1, 10 at 14:58

I've got a Mercedes 84' TD (diesel). I have about 1/2 gallon of old gas and a small amount of two cycle mix that I need to dump or use up somehow.

I know that one can add small amts of gas (5% or so) to blend with a tank of diesel, similar to what farmers do to run some equipment in the winter. So I'm wondering if I can just dump this leftover stuff into a fairly full tank of diesel. I suppose the only concern would be if any varnish has settled out in the mix, but I'd think it would likely still be fine..or do I have to still worry about my injectors.

Thoughts? Thanks.


Follow-Up Postings:

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RE: diesel & adding some old gas

I firmly advise against adding anything to the fuel for your diesel. Your county should have a recycling center that you can dispose of the old gas and oil at.


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RE: diesel & adding some old gas

Yes, but that's almost too easy. I'm just trying to get a sense of the risk of adding it to the tank. I probably won't do it, since I'm worried about the injectors, but anyway.

The reason I'm curious to try is because I once had a gas station attendant accidentally fill up my diesel Suburban with gas (even though I parked at the diesel pump and it's labeled "diesel only" above the cap. They had to drain the tank, but afterward I was still concerned that it couldn't be pure enough. That's when a farmer who was filling up told me about the gas/diesel blending thing in the winter. So all was well after I refilled the tank with diesel.


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RE: diesel & adding some old gas

Just one thought on this " ARE YOU OUT OF YOUR GOD DAMN MIND " ? Unless you own an engine shop or have lots of spare engines laying around go for it. Farmers don't add gas to their equipment. They use kerosene or Varsol. 2 stroke oil doesn't burn it vaporizes. Ever wonder why a 2 stroke always smokes ? Do what you think is best for you.
Just my input.Good luck


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to clarify

Nice comment. I'm not out of my mind, and I also don't think you understand what I'm saying.

Read this and maybe you'll understand. (Cut and paste the whole thing into your browser.) Have a good one.

http://www.turbodieselregister.com/mixing_gasoline_and_diesel.htm


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and by the way...

By the way, after reading that link I know more about it and won't do it.....but it does demonstrate that the idea is out there and has been done from time to time.


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RE: diesel & adding some old gas

Back in 1983 my Dad had a Vauxhall Astra 1.6 diesel, one of the first diesel cars to sell in any number here. Back then the diesel on sale was fairly crude and it tended to go gloopy very easily in winter. The truckers used to light fires under their diesel tanks but that wasn't an option with a domestic station wagon. He regularly added a drop of petrol to the diesel and it worked fine. Stopped the diesel getting too gloopy and the car still ran (not as well as if it were on pure diesel, but that wouldn't happen at all at this temperature).

Nowadays with all the electronics and sensors on modern engines I wouildn't risk it, and in any case diesel now has additives to stop it going like jelly when the thermometer dips below zero.


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RE: diesel & adding some old gas

Fuel jelling at cold temperatures has always been an issue with diesels. Additives specifically designed to match your engines requirements are OK, but home remedies should be avoided. Once your engine is started engine heat, fuel heaters in the separator assembly etc all work together as a complete system to ensure your engine works correctly. In extremely cold climates some resort to even having heaters not only in the engine block but in the fuel tank itself. Would gasoline cut the fuel enough to reduce some gelling? Yes it can. But gasoline does not lubricate to the level that your injection pump and injectors require. This is also the fatal flaw in the "french fry oil" or "veggie" diesels. While the engine can run on these fuels, your risk of component damage and the corresponding cost of repairing it makes it something that is unwise for the average owner.


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RE: diesel & adding some old gas

Thank you for the explanation.

As for veggie conversions, I was interested in that a couple years ago and did become aware of the caustic issues you mentioned. On the other hand, at the very least, it would afford a last resort "emergency back-up fuel" option. (Imagine loading up on 20 gallons of Costco fry oil someday - it's not cheap, but it would be there.)


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RE: diesel & adding some old gas

This isn't quite on topic but may be interesting:

About 1980 an outfit for which I drove truck went thru a period of mixing engine drain oil into the diesel fuel. They had a special mixer with a pipe into the primary tank to fully circulate it for thorough mixing. Most engines lasted at least 500,000 miles. These were the big old Cummins engines.

On a whim I just now Googled >>mixing engine drain oil into diesel fuel<< seems to still be an accepted practice.


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RE: diesel & adding some old gas

Didn't mean offence to anyone but up here jelling of diesle or heating oil is unheard of. We have " summer oil "
and " winter oil " Our diesles will, or supposed to start at -20F. NOT plugged in and they do with almost no smoke.
The Volvo truck is garrantied to start at 20 below without being plugged in. They don't but the kenworth's do. Our diesle cars use circulating fuel pumps and most highway trucks have heated fuel lines and tanks. That is why there are Canada cars and U.S. cars. If a poor sap still has summer oil in the tank in the winter forget about starting that vehical. Winter oil can be as high as 40 percent karosene blended with anti jell and anti fungus with a moisture inhibiter and yes the price goes up. Anyway putting gas or any other additive not normally blended into
diesle oil is not recommended. The engine was not designed
for that. As far as putting acid and water contaminated engine oil into diesle fuel I think they're nuts. " Most engines lasted 500,000 miles ". They should last 1,000,000.
miles. A V6 car engine on gas will last 500,000 miles.
Well to each his own.


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RE: diesel & adding some old gas

just use it to kill weeds, dont chance your cars engine.


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RE: diesel & adding some old gas

One place to get rid of a gallon or so of 2-cycle gas/oil mix is in an old lawnmower engine; not the 20 hp riding mower, but the one you have to push around. The oil lowers the octane rating, so if it casues knocking, dilute it with more gasoline.

However, mowing season is several months away and by that time that stuff will be stale and moisture contaminated. It may cause misfiring.


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RE: diesel & adding some old gas

Gasoline in a diesel car? Seriously?


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RE: diesel & adding some old gas

Some old mechanics apparently used to do it to keep diesel fuel from gelling up in the winter. That's the reason I posted this originally in 2010 (two years ago).


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RE: diesel & adding some old gas

I wouldn't use anything but diesel fuel in a diesel, but I used recycled fryer oil (biodiesel)in all 4 of my GM 350N diesels back in the day and they never missed a beat. The corrosive problem that is referred to is a result of short cutting the oil distillation (refining) process. The "quick filter" method doesn't remove the water from the fuel and this causes the formation of acids and promotes corrosion.


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