trailinone

My friend drives a late model Duramax. Each oil change, he dumps the burnt oil into his fuel tank, if it's close to full. He says it does not hurt a thing. Opinions?

torquefan

From reading on here, it is a common practice with the older trucks and the old oil will mix and burn with the fuel well. I, however, would want to filter it as fine as possible to remove wear metal before adding it to the tank.

The new common rail systems run at much closer tolerances and at much higher pressures, and seem to be much more trouble-prone anyway, so I think I would stay away from them with any questionable fuel source.

1985cucv

i would not do it!

isb07

thats nuts if you ask me, thers all sorts of small particles in oil and if the filters dont catch it, all thats getting sprayed in your cylinders at 20k psi. i dont see it helping a thing.

Lary Ellis (Top)

I have done it on my 2nd gen 12 valve, filtered it well and mixed it to 30% oil 70% fuel back when fuel was $5.00 a gallon. Worked REALLY well but I would NOT do it in a 3rd or 4th gen truck, different animal altogether.

Raspy

I'm with Lary.

I put a lot of used oil through my old Mercedes diesel, my 1st gen Cummins and the Perkins diesel in my boat. Never a problem.

Many guys with diesel powered boats simply drain the crankcase into the fuel tank when changing oil.

But the third gen might not like it so much. Mainly I'm concerned about the CP3. Clean lube oil, two stroke, or heating oil, fine. But no tranny fluid or used engine oil for me.

DodgeDiesel61

Yeah, with the price of injectors and injection pumps, it would not be worth it to me.

As others have said, the 12v mechanical and Mercedes diesels will burn anything but water... the CR motors, not so much.

annabelle

Price of a new engine vs fuel savings.......fairly easy call in a 3rd or 4th gen.

Raspy

annabelle,

It's really not the price of a new engine vs fuel savings.

It's just personal preference based on a persons fear level. You would not be guaranteed a failure that you then had to amortise over the life of using waste oil.

I've asked over and over and have never seen any concrete evidence of a failure from burning used engine oil. But it just seems a bit more risky in a third gen than in some other designs. Also, I rack up a lot of hours on mine and not so much on the other engines I happily ran it in. It is a very common practice in some circles.

Also, the Duramax has a CP3 and the guy mentioned in the original post does it at every oil change with no problems yet, whatever that means.

annabelle

Well, I may have exaggerated about a complete engine. The chance of messing up my injectors or pump does raise my "fear" level to the unacceptable level for me.

tesla440

in same quantities it will not be that bad. I personally have done mixes as high as 50/50. But I also filter mine til 1micron & then put it through a water/fuel seperator & then into the tank. I can run 30/70 oil/#2 without any issues & have done so for 30,000+ miles. No issues as of yet.

annabelle

Have a buddy with an 07. CP3 went out . He had been using the oil from the farm equipment and his Dad's truck to cut the diesel....Long story short, Dealer tested his fuel and voided his warranty.

AlCorr

I wouldn't do it. If you have to dump it somewhere because you have to use it, filter it and dump it in with your home heating oil.

SpeedyWS6

If you filter it well I wouldn't be scared of it. I ran my truck on a 50/50 mix several times.

DodgeDiesel61

Don't take this the wrong way tesla, but 30,000 miles is not a very long time in the life of a motor/fuel pump/injection pump. If you can find guys that are running unfiltered waste oil for 2, 3 or 400,000 miles without any problems, then I would say it is safe.

Again, no offense meant; to each his own.