Burning used oil through our engines - PeachParts Mercedes-Benz Forum

GregoryV022 · #1 10-25-2011, 02:13 PM

So out of curiosity, after i drained the oil from my 300TD, i decided to pour 2 gallons of it into my fuel tank to see if it would burn.

thinking back on that, im wondering if that wasn't be best of ideas.

please advise.

thanks in advance.

boneheaddoctor · #2 10-25-2011, 02:24 PM

Bad idea....there are a lot of contaminates including soot that are abrasive to the injection pump. So while it will run....for a while....you are going to shorten its life.

vstech · #3 10-25-2011, 02:27 PM

2 gallons will cause some wear, but mixed in with the tank it's not the worst thing as long as you don't do it on a regular basis. you tried it, it burned, don't do it again.
some members here have centrifugal cleaners for the oil, and they soot filter it, and use it as a fuel...
I'd not recommend it...

Mad_Matt · #4 10-25-2011, 02:30 PM

Oil is oil but used oil can be hard on the injectors and the injection pumps. It's full of carbon as well as other containments including additives and anything over 25 microns can cause damage. If you want to burn old engine oil I'd run it through a 10 micron fuel filter and mix is with diesel fuel to insure its viscosity, flash and pour points stay close to that of diesel.
I've considered doing the same thing in mine but don't have an electric FP with a filter head attached to run the oil through on it's way to the tank.

There are some oil bypass systems that run a small portion of the engine oil into the flue system to be burned. They all look like gimmicks to me.

vstech · #5 10-25-2011, 02:37 PM

... I'm thinking MUCH smaller filtration is needed for the IP to flow without damage than 10microns...
I'd be uncomfortable with 2 microns filtration on USED MOTOR OIL!!!
the BOSCH pump has REALLY tight tolerances.

Mad_Matt · #6 10-25-2011, 02:49 PM

I agree that more filtration is better but most Diesel Filters are only 25 microns. I'm still on the fence personally becaue of the other additives in engine oil.

Diesel911 · #7 10-25-2011, 05:20 PM

Quote:

Originally Posted by Mad_Matt

I agree that more filtration is better but most Diesel Filters are only 25 microns. I'm still on the fence personally becaue of the other additives in engine oil.

The Secondary Spin-on Filter is listed as a 10 nominal Micron Filter. However, nominal Micron means it has a 50% efficiency rating at 10 microns.

vstech · #8 10-25-2011, 02:52 PM

I thought the primary filter was 25, and the secondary was 5 or 10?

Biodiesel300TD · #9 10-25-2011, 03:12 PM

There is a reason we use motor oil as a lubricant and not as a fuel. It burns really dirty. Think of the smoke from burning a quart or two in a few thousand miles, now imagine a gallon or two over 300-400 miles. Smokey and the bandit. Give a Hoot, Don't Pollute!

Best thing to do with it is to recycle it, or burn it in a waste oil heater.

weird beard · #10 10-28-2011, 04:15 AM

Quote:

Originally Posted by Biodiesel300TD

Give a Hoot, Don't Pollute!

Best thing to do with it is to recycle it, or burn it in a waste oil heater.

Burning used oil in a furnace still sends all the heavy metal contaminants into the air. Don't worry, not preaching, I burn it in my garage furnace!

I burned used motor oil in my last car, as well as WVO, as well as ATF, or a combination of all the above, as well as anything else I could find for free, anything to not have to burn diesel! Although the car was a junker and only drove for a year before scrapping, never had ill effects from the various cocktails floating around the fuel tank. I wouldn't do it to my SD or recomend it, just reporting. (the fumes from my exhaust would burn your eyes)

GregoryV022 · #11 10-25-2011, 03:22 PM

probably should have clarified i had almost a full tank of fuel when i added the used motor oil. so it will have been diluted somewhat.

ive been running on this mix for about 60 miles now and if anything the engine runs smoother. but i hear that the general consensus is that unfiltered oil will cause undue wear on my IP and other internals.

is there any other course of action i should take at this time.

vstech · #12 10-25-2011, 03:47 PM

when you get the fuel down below R, I'd change the fuel filter... don't change it before you run out though. ( most filters catch the most when they are dirty...)

BrianCostello · #13 10-25-2011, 05:26 PM

This habit came from the old diesel boats (like tug boats) of the 60's, 70's and into the 80's.

Some ships/boats had the used oil pump direct into the fuel tanks!! but you must realize it would be 15-20 gallons of used oil, into 2-3000 gallon's of diesel fuel about .01%

2 gallons into a 18 gallon tank is .11%. . . .a bit higher. and not advised. I say only run 1/2 tanks for the next 4 fill ups. So you keep diluting it.

Brian

Diesel911 · #14 10-25-2011, 05:27 PM

Despite the fact that I had advised against burning used Motor Oil as Fuel I tried out of curiosity; 2 quarts of used Motor Oil in my Volvo Diesel.
(However, I filtered it through a 2 nominal micron Filter Bag before it went into the Tank.)

It makes the Exhaust gas stink! And, it stinks even after the Tank was refilled with only Diesel Fuel.

Motor oil has additives in it to retard burning and used Oil can have acid in it.

It also has an Ash content to it. Ash content is actually Metal.

GregoryV022 · #15 10-25-2011, 05:45 PM

Filtering it probably would have been a good idea. ill keep filling up at half tank to dilute the mixture until the fuel in the inline filter comes through clear (its black right now). then i will change the spin on filter.

i sure hope i haven't done to much damage.

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