Putting used motor oil in your diesel fuel?!

[Dargo]

I was filling my pickup with diesel at my local Co-Op yesterday and I watched some guy next to me pour a couple of quarts of used motor oil into his fuel tank while he was filling up. /forums/images/graemlins/shocked.gif Trying to be as polite as possible, I asked him what the h*** he was doing!!

He was an older guy and he told me that he had been doing that for years and it gave more lubrication to his diesels and increased his cetane level. Am I in the dark, or is this guy nuts?? Other than perhaps lowering the population of mosquitos, and insuring that your exhaust system will never rust, all other effects I can imagine from this practice would be bad. Let's see, more pollution, clogged fuel injectors, clogged fuel filters, heavy dark blue/black smoke etc. etc. Anyone else heard of this? It sure seems nuts to me. /forums/images/graemlins/confused.gif

 

[SkyPup]

It is nutz. But then again old diesel experts used to routinely pour used transmission oil, radiator fluids, brake fluids, kerosene, gasoline, and whatever else they thought their diesel engine would burn.

 

[Junkman]

Skypup.... before you go accusing us old timers as being NUTZ, I find a compelling reason to disagree. Way back when Rex was a pup, it was common to put a quart of automatic transmission oil into the diesel fuel because the cleaning properties of ATF would clean the gummy residue off of the injectors. In fact, it was even recommended by Mercedes Benz and some of the other engine manufacturers to use this first before doing any injector work. Having said all that, as you have pointed out, using any of the other items is just NUTZ. The contaminants in the used motor oil will just clog the filters. Fifty years ago, you could put just about anything into the tank and the old diesel engines would just digest it without even a hick-up. Times have changed. At least if he is going to use used engine oil, he should at least use synthetic for its longer lasting properties that might relate to better milage.... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

The proceeding has been presented for your educational benefit and to add some humor to a already dry forum. I will now retire to my Greeters chair at the front door of Woodstock Walmart ... /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif

 

[JimR]

My dad use to put Mystery Oil and tranny fluid into the gas tank of his cars. He said it was for upper cylinder lubrication. Dirty oil will only plug the fuel filter. Maybe he's just too lazy to bring it back for recycling. Or better yet, feels he can get more mileage out of it by burning it in his truck

 

[SkyPup]

Way back then, the diesel fuel available was indeed allot crudier for sure, although injector nozzle holes were much larger diameter than they are today, back then they were measured in millimeters, now in microns.... /forums/images/graemlins/wink.gif

I even heard of old diesel experts that used to pour battery acid (sulfuric acid) through their injector nozzles to clean 'em up too, and hey it even works much faster than the ole misguided transmission fluid technique!

It is a true testimony to the advances in diesel fuel technology and diesel engine technology that all those old methods from the good ole dayz are no longer valid.

 

[Junkman]

The manufacturer of Marvel Mystery Oil used to produce a product that you would install under the carburetor of a engine and it would inject a very small amount of MMO into the intake of the engine as the atomized gasoline was headed to the cylinders. This plate was made of aluminum and about 1/4" thick. There was one metering hole for each barrel of the engine, but never more than two. Connecting to this plate was a rubber hose that went to a glass container that held the MMO. I had seen them on cars in the 1960's and on one occasion, I had the opportunity to remove a intake manifold and head a V-8 engine (Oldsmobile 330c.i.) that had used this method of upper cylinder lubrication. I was amazed at how clean that portion of the engine was. I never got into the complete engine, because we were just removing a broken stud from the head, but it looked like new on the top end. The engine had about 60,000 miles on it. There was no carbon at all on the pistons or around the valves. The owner used Amoco unleaded gas back when they were the only ones producing "clear gasoline". I always wondered how they got the octane as high as they did without the use of lead. That also might have been the reason for the clean upper end, as that it what Amoco marketed it as being good for.

 

[Soundguy]

Wow.. I drain 'used' motor oil out of the engine.. why would I want to put it back in! Seems like way too many contaminants. If it was a lube issue.. use new oil! or power service!

Soundguy

 

[tillerkiller]

Over the Road Trucks (the big'uns) used to mix their old engine oil (that was removed during an oil change) with the diesel fuel in their regular tanks. There was a machine that filtered the oil and mixed it in really good with the diesel. I don't know the ratios or anything, I just saw the machine that did the mixing and asked what it did. This was like 15 years ago, don't know if this still goes on or not.

 

[Junkman]

If it has stopped, with the rise in the price of diesel, it will probably get started again. I have seen a lot of new machines that clean everything from transmission oil to anti freeze and reinstall it into the vehicle. The one common problem with this new technology is the cost of the machine vs. the savings. Usually it isn't cost effective but for only the largest of fleets. That is why car dealers don't use them more. We have the technology, we just haven't been able to get the cost differences aligned. As product prices rise, the gap will become less and we will see more recycling of fluids. Think of it as dialysis for your engine.... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[Richard]

</font><font color="blue" class="small">( Way back when Rex was a pup )</font>

uh... would that be "T-Rex"?

(ok, I'm ducking for cover now)

/forums/images/graemlins/grin.gif /forums/images/graemlins/wink.gif