I would like to hear the opinions to see if this is ok or would actually damage something.

My neighbor is a diesel mechanic and we were talking about where to dispose of the used motor oil after changing it. I would just take it to autozone where they dispose of it no charge but he told me that he just dilutes a couple of quarts at a time into his fuel tank and as he put it "burn it up". Now he has a dodge cummins but he claims its fine to do in any diesel engine. His theroy is that it will help lubricate some of the internal parts and its a bit extra fuel you don't have to pay for.

I have heard ATF is ok but never heard of used oil. The only think I could think off hand is that it would clog the fuel filter faster but just want to hear what others think.

 

That part about burning it in the fuel tank is true, but doing so can clog the cat up. This a warning on Ford diesels. I say first why re-use it, it just adds wear to something and extra carbon. On the Kaiser trucks an engine made by cummins years ago it was called a multi fuel, so it was suppose to burn anything petro. But it didn't work so well because they quit making it. You know if I needed to save money and use my used oil then maybe I don't need a diesel in the first place!
I wanted to comment on your idea, that you would take the oil to auto zone. Ding Ding Ding you get the the prize, you know 30-40 years ago that method was very exceptable, but if I'm correct that engine now has 24 to 36 plus valves and a computer and other stuff motors back in the day didn't have, and you notice they don't smoke as they once did. So I say bad idea all round cost too much to get them fixed.

 

Our IP's are meant to use clean deisel fuel due to fine tolerances of moving parts. If you have ever done an oil sample and seen how much crud can be in the oil, you would understand why I do NOT recommend using used oil in the fuel. There are special fuel additives for lubrication that are a lot cheaper than a new IP.

 

I'll agree it's probably a bad idea for the pumps sake. It will also dirty fuel filters a lot faster, but if it's an old beater, with the price of fuel nowadays, I'd be doing it too.

The more I think about it, ever notice how black the fuel filters are in old Powerstrokes? The oil creeping into the fuel doesn't seem to hurt them. Hmmmm.

 

I would never put used\nasty oil in the fuel, why would you want to put all that dirt thru the pump and injectors? That's about the same as putting used oil in your motor, ATF is very safe and good for cleaning and lubing as long as it's not the ATF with the addifiers. Gettig a pump or injectors rebuilt is big money!

 

The motor oil has more BTU's than diesel, so it does have more power.
Clog up what cat? No cat or muffler on mine to clog up.
The used oil does have a lot of garbage in it, sulfides, metal, and carbon.
So I would not burn used oil, I might dump a quart or two of new oil in mine though.
And I also run ATF in my fuel every couple of tanks.
Just don't use the red kind, or you may be in trouble with the tax man that thinks you are running red fuel.

But I also have a friend that gets a good deal on JP4 jet fuel.
That is what he has been running in his IDI for years.

 

Several years ago (20) there were some companies that were mixing used motor oil with their diesel storage. They were running the used oil thru several filter setups before mixing. The mix was very minimal, I do believe it was a maximum of 5% into 10,000 gallons of diesel. I spoke to several of the drivers and they said they were having to change the filters in the mixing station every day. It got to be more a pain in the butt and not worth the hassle. I havent heard of anyone doing this since. I wouldnt do it in mine. Its his truck and your truck ... enjoy the fun.

 

You mean JP-5/8 is jett fuel, JP-4 is fuel oil. used for ships to burn. JP-5 is rough running on the engine than Diesel, it will work but has been known to run rougher.
I use red diesel in my tractor, seems alright I use seafoam every couple of tanks to keep her going right.

 

I know that these deisels would run on a wide range of oils but when I change it and see how black and cruddy the oil is why I've always just taken it to autozone to get rid of it. I couldn't see how running that black oil back through the motor would be more benificial than it would harm it. It did make me wonder because he has over 400K miles on his truck without having any major problems. I guess he has just been lucky. Sounds like if it's filtered enough it would be fine but I agree why go through that much hassle just to save a few cents. My time is worth more than that.

 

Goodie, I agree with you on the time bit. You know I say if it ain't broke, then leave it be! And again the grit in that oil has go to go some where?

 

maryland smib,
this is from OSHA

Chemical Sampling Information
Jet Fuel(JP4)
Chemical Sampling Information - Table of Contents Field Definitions
Analytical Methods

General Description

--------------------------------------------------------------------------------

NAME: Jet Fuel(JP4)

SYNONYM(s): JP4; JP-4

IMIS: J105

NIOSH: RTECS NY9340000; 45545

DOT: UN1863 Flammable Liquid

DESCRIPTION:

A mixture of aliphatic and aromatic hydrocarbon compounds of which meet the requirement of military specifications MIL-J-5624E (AMRL** TR-74-78,74) [Aerosp Med Res Lab]
MW: 85


So I guess you are talking really fast boats.

 

People do the oddest things. I read in an old Tom McHall (sp?) article where this guy would drain the oil from his car then run the engine a few minutes with the drain plug out to make sure he got all of the old oil out. LOL, ouch!

 

There's a good practice!

 

JP-4 is military jet fuel. Civilian jet fuel is Jet A. Every military jet there is uses JP-4 as far as I know. I crewed a C-135 (Boeing 720) for 4 years and it burned JP-4. Some fuel trucks used at airports use Jet A but I've heard it's not a real good idea ..

EJ Stith

 

Maybe I should mention that to my neighbor to make sure he runs it to get all the oil out before he runs it back through. Great Idea!