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Discussion Starter · #1 ·
Hello all, yesterday I changed my oil and poured the entire 2 gallons of hot motor oil into my fuel tank thinking that because it was hot, it would just dissolve into the full tank of fuel I had and all would be good.

Well apparently that didnt happen, I started it up this morning and it ran ok for maybe 30 seconds, then it started getting a little combustion knock, check engine light came on, and it has gotten hard to start.

Im hoping the fuel became too dark for the optical sensor to see thru. i have dtc 17 18 35 54.

Ive drained all but a gallon or so of the fuel out of the tank, and will replace with fresh diesel later this evening and see what happens.

I was wondering, with the fuel being much darker, almost black, WOULD that be enough to cuase these problems, or have i done more serious damage to say the injector pump?

Any thought plz,

Thanks
 

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Im Sure The Fuel Filter Didnt Like That.2 Gallons Or 2 Qts...HAD TO EDIT I DIDNT SEE THAT IT WAS A 6.5.IM NOT TO KEEN ON THOSE
 

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I wouldn't try that again, motor oil will leave alot carbon buildup in pistons and heads, hard on the fuel system, and its just not something that you should do again, I would flush the fuel system and definitely change the fuel filter a few times!! Let this be a lesson why one shouldn't use motor oil as fuel.
 

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There are still people who thinks, that they can run used motor oil as fuel or fuel additive. Sorry, but the only thing i can thought about this is "dumb, really dumb !".

NEVER runs motor oil, either new or used as fuel or fuel additve.

Spend a few bucks more to buy a additve like standyne, 911, diesel kleen, to name a few or usa 2-STROKE-OIL ! THIS OIL IS MADE FOR BURNING !

Cu,
Sven

BTW : Get the crap out of your fuel system, flush it, change the filter a few times and hope, the porblem is gone.
 

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There are still people who thinks, that they can run used motor oil as fuel or fuel additive. Sorry, but the only thing i can thought about this is "dumb, really dumb !".

NEVER runs motor oil, either new or used as fuel or fuel additve.

Spend a few bucks more to buy a additve like standyne, 911, diesel kleen, to name a few or usa 2-STROKE-OIL ! THIS OIL IS MADE FOR BURNING !

Cu,
Sven

BTW : Get the crap out of your fuel system, flush it, change the filter a few times and hope, the porblem is gone.
to date, nothing has worked better on my balance rates(duramax). even running 2 gals though out the winter per tank. however, i do filter mine before i pour it in.


oh yeah, just call me dumb;) 80k+ miles, balance rates have never been better.




Aoelian, did you pour the oil in first then fill it up?
 

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Hey Moss, what are balance rates?

As for mixing dirty old oil in the fuel, that is plain insane. The reason the oil is black is becuase of all the deposits in it......and now you want to throw that crap into your injctors, and pump. You have the balls.! Hopefully it all works out.

The saying "A little knowledge is dangerous", comes to mind.

We should start a thread of all the silly things we have tried, we could all have a good laugh, maybe call it, "the jokes on me" thread! hahaha. But I'm not going to be the first.
 

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i did the same thing to my 97 6.5td about a month ago, and it instantly ran like crap because of the dirty motor oil, optic sensors dont like dark oil. i will not do that again!
 

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There are a lot of opinions floating here without experience evidently. I have been burning my used engine oil in with my fuel for about 15 years in all sorts of diesels, Cummins, Cat, John Deere, Powerstroke, Duramax, etc. and have never had one problem with pump, injectors, or any part of the fuel system on any of them. The only trouble it has ever caused me, is it don't want to flow through a Duramax fuel filter very good when it's cold and you pour a whole oil change in when the tank is less then half full. One of the engines is a 855 Cummins with over 700,000 miles at 600HP and the only thing done to it has been to run the overhead (adjust the valves). Been burning all it's own oil changes since it was new. I just cant see changing my ways with the success I've had.:cool:
P.S. On a tractor with a consistent load, I see 2 psi. more boost with the oil in the fuel at 5% mix.:D
 

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There are a lot of opinions floating here without experience evidently. I have been burning my used engine oil in with my fuel for about 15 years in all sorts of diesels, Cummins, Cat, John Deere, Powerstroke, Duramax, etc. and have never had one problem with pump, injectors, or any part of the fuel system on any of them. The only trouble it has ever caused me, is it don't want to flow through a Duramax fuel filter very good when it's cold and you pour a whole oil change in when the tank is less then half full. One of the engines is a 855 Cummins with over 700,000 miles at 600HP and the only thing done to it has been to run the overhead (adjust the valves). Been burning all it's own oil changes since it was new. I just cant see changing my ways with the success I've had.:cool:
P.S. On a tractor with a consistent load, I see 2 psi. more boost with the oil in the fuel at 5% mix.:D
Did you filter it first? or just dump the dirty oil. I think he dumped 7 quarts of straight dirty oil?
 

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I use a very clean bucket or pan to catch it and pour it right in. I figure the oil has been through the engine oil filter thousands of times already. It may make a difference that I try not to let my oil get extremely black before I change it.
 

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Discussion Starter · #11 ·
Ok , I emptyed the fuel tank(plus or minus a gal) and refilled with fresh fuel, I took it for a test drive and it ran better but still knocking like crazy(combustion knock) ses light stayed on, got it back home and shut it off, restarted it, it went back to normal right away upon restart.

some observations; apparently the optic sensor has a lot to do with the timing. when it got dirtied up, I can only assume that somehow the computer was fooled into thinking it needed to advance the timing, or being totally inoperative, it defaulted to a much more agressive timeing setting.

During the initial test run, but before the problem went away ,I did notice a good bit more power when I "got on it" so im going to look into the optic bump since it seems obvious a little more timeing would help, I wouldnt go nearly as far as this was tho ;)

I did not filter the oil, I simply dumped it into 25 gals of fuel. the oil was hot, so I had hoped it would just dissolve into the fuel.the next day it was a cold morning, an I think I basically sucked 90% used oil off the bottom of the fuel tank.

Ill probably never put 2 gallons in like that again. will definetly try and time my next oil change to precede a trip to the fueling station, where i will add a gallon and then fill up.

was a dumb mistake, in the way I did it, and not imo, to use up the old dirty oil that way.

Thanks for the replies :)
 

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Let's put some analysis to this discussion.

First, just because someone does this, doesn't make them "dumb". Maybe is was curiousity, perhaps advice from another person, whatever.

But, just because you've done it once, or even 100 times, doesn't make it a good idea either. Just because you've done it and not had bad experiences, still doesn't make it a good idea.

Here's why. The reason the motor oil is black is chiefly due to the fact that there are unburned hydrocarbons in it; you commonly call it "soot". There are other insolubles, and all kinds of other wear metals in used oil, but the "soot" is what turns it black. And that soot is some of the most abrasive material known. And in the oil, the soot is also small; really small. So small in fact that no full flow filter can get it out, and even bypass filters stuggle to get it all. Soot can be smaller than 1 micron quite often. It also likes to agglomerate (join up) with other soot particles. And bouncing around in your tank isn't going to break up the soot carbon bonds, either.

Now think of your fuel system. The lift pump (no matter what brand or type engine) has to draw this fuel contaminated with soot up into the main pump body. The carbon wears on all the parts. Then, the soot-laden fuel goes to the fuel filter. Typically, fuel filters are nominally rated anywhere from 4 to 10 microns. Some are rated down to 2 microns, but even that isn't sufficient to stop the soot. So, the soot now travels to your high pressure pump, and then to the injectors. Along the way, it's scratching and wearing everything it can find.

In the old days, perhaps with old mechanical, low rpm, low pressure diesel injection pumps and in-direct single hole injectors, you might be able to get away with this for a while. Today's new high flow, high pressure pumps and multi-hole injectors DO NOT like this kind of treatment.

Do as you see fit. Just don't complain when somthing goes awry. You've been warned.
 

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I used to run used oil through my Detroit Diesel 430 HP. Never a problem. As a matter of fact; Schneider used to have a bunch of International COEs with an add on system which recycled the oil directly from the engine. You would add clean oil to the reservoir then the system would pull oil from the motor and pump it into the tanks. The idea was to extend oil change intervals and just change filters. These were on pre 2000 motors. Don't know if they are still in use. Just an idea. http://www.heavydutytrucking.com/2002/03/114a0203.asp
http://www.embedded.com/story/OEG20010618S0078
 

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I used to run used oil through my Detroit Diesel 430 HP. Never a problem. As a matter of fact; Schneider used to have a bunch of International COEs with an add on system which recycled the oil directly from the engine. You would add clean oil to the reservoir then the system would pull oil from the motor and pump it into the tanks. The idea was to extend oil change intervals and just change filters. These were on pre 2000 motors. Don't know if they are still in use. Just an idea. http://www.heavydutytrucking.com/2002/03/114a0203.asp
http://www.embedded.com/story/OEG20010618S0078
Maybe I'm not crazy...........

Just some logic to stimulate the thinker;
If the used oil is so dirty, and the black carbon in it is so abrasive, wouldn't the last 100 miles before an oil change wear the engine out?
The engine oil is what lubricates the injection pump on the drive side of the pistons and gears right?
I think most engine oils are formulated to not leave soot deposits and burn clean in engines that have less than perfect or worn rings and tend to burn a little oil on their own.
I don't have the answers, I'm just thinking here.:cool:
 

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Engine Oil is very different from diesel though. Oil has an additive to keep the soot in suspension and allow the oil to do it job. Once you combine it with diesel, the additive is sure to break down, since diesel acts like a solvent, and as stated here in an earlier post, can and will clog up a fuel filter in a hurry, and can do some damage to your fuel system. I would think new, un-used engine oil mixed with diesel might return some lubricity increases...(see lubricity study) but I would just stick with one of the more widely available fuel additives.
 

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firefighter 503, the whole point of changing oil is to remove the contaminants before anything abrades "during the last 100 miles before an oil change wear the engine out?" Besides, it's not accurate to attribute the accumlation of abrasives to such an accelerated, almost exponential, growth rate.

Also, you answered your own question by talking about the drive side of the pump. That is where the engine oil belongs. But on the driven side (fuel side) of the injection pump, the tolerances are MUCH tighter. And the metalurgy is different for the high pressure side as well. That's why soot on drive side is not as detrimental as soot on the driven side. Again, I'll point out that a traditional full flow oil filter is rated around 20um nominally, but a diesel fuel filter is rated at perhaps 6um nominally. The reason for the tighter filtration for fuel compared to engine oil is because there is less tolerance for contamination in the fuel system components; it's just that simple.

And bartman brings to light an excellent point. If we were to get 5% fuel in our engine oil, it would start to become significantly detrimental, rendering the additives and characteristics of the oil nearly useless. Yet, if you put 2 gallons of used oil into a 40 gallon fuel tank, you've got 95% fuel in your oil! That will break down the composition of the oil quickly, and all the abrasives will be freed again, no longer contained by the dispersants and dropping out of suspension, ready to wreak havoc on any available surface.

Monkeywrench14 brings up a good point. It used to be known that you could run some old oil in your fuel. But I made that clear in my previous post as well. But the fuel systems of the 6.5 and 6.6 diesels are not made to experience that type of fuel condition. The DD he had was specifically designed to run such a fuel product. He even spoke of a replenishment system that purposely dosed a measure amount over time. There's the big difference. The DD was designed to run on used oil, introduced into the fuel at a specified rate. The 6.5 and Dmax were never designed to run on used oil in the fuel, at any rate. What's ok for one engine design is not necessarily good for all engine designs. The practices of yesteryear are not acceptable in today's diesels.
 

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I used to run used oil through my Detroit Diesel 430 HP. Never a problem. As a matter of fact; Schneider used to have a bunch of International COEs with an add on system which recycled the oil directly from the engine. You would add clean oil to the reservoir then the system would pull oil from the motor and pump it into the tanks. The idea was to extend oil change intervals and just change filters. These were on pre 2000 motors. Don't know if they are still in use. Just an idea. http://www.heavydutytrucking.com/2002/03/114a0203.asp
http://www.embedded.com/story/OEG20010618S0078
Not to condone burning used Oil, as I wouldn't do it but older 2 cycle detriots have a much more forgiving fuel system. NO IP .
 

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This is just my opinion, but would you rather burn your own USED dirty oil or spend an extra $7 on 2gal of fuel. I'd spend $7 on fuel without thinking about the damage that "could" be done by burning your old oil. I know that you Can burn your old oil but I'd rather turn that in to an oil recycling center and spend $7 on fuel.
 

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I've run quite a bit of used oil through my diesels over the years, but I haven't and won't run it through the Duramax. In my experience, I always filtered the used oil. I never ran more than 1 gallon per tank. I would add it prior to the fillup. Also, I would mix diesel with the remaining oil in the jug and pour it in the tank.

I never had a problem running on it, and actually it ran quieter than with straight diesel.

I stopped because overall, it was more of a pain than anything else (not to mention cleaning up a spilled gallon of dirty motor oil on my concrete floor wasn't worth doing that again.)
 

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i guess i will keep destroying both of my motors.

another way to look at it. the crank and rods and pistons in your motor is lubed by oil. the crank rods and pistons in the cp3 are lubed by the fuel. would you run straight diesel in your motor? diesel fuel doesnt have the same lubricity it used to. i dont care what they say, its not the same.
 
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