Used oil in my gas tank?

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Is there any downside to taking used motor oil, filtering it thru an oil filter, and adding to a gas engine, perhaps at 1qt per 20 gallons (80:1) ratio?
 
I can see doing that to a diesel, but never a gas engine. I expect you would gunk up the motor, clog the cat and maybe ruin your O2 sensors.
 
A four-stroke engine? You fogging for mosquitos? You ran out of fence posts to paint with used oil?
Matt: you would let used engine oil go through the diesel fuel pump? Yikes!
 
quote:

Originally posted by Tosh:
A four-stroke engine? You fogging for mosquitos? You ran out of fence posts to paint with used oil?
Matt: you would let used engine oil go through the diesel fuel pump? Yikes!


Do a search. There are threads about that on this board. I believe the consensus was that a small amount of used oil won't hurt it.
 
I don't know why you'd want to do it, however, car manufacturers over there seem to think that 1 quart per 1000 miles is perfectly acceptable oil consumption.
freak2.gif


So if you stick to 1 quart per 1000 miles as your total consumption (useage plus added), I doubt that you would be destroying anything.

at 25MPG, that 1 quart to 40 gallons.

I do not recommend this course of action, however.
 
I guess the question should be "Is there any upside to taking used motor oil, filtering it thru an oil filter, and adding to a gas engine, perhaps at 1qt per 20 gallons (80:1) ratio?".
 
I've done this with my Rabbit Diesel ..but I don't know if it was "wise".

I wouldn't be too worried about the engine...per se~ ..nor the emission controls/sensors. I'd be more worried about the fuel system (strainer/injectors) since you're introducing way more contaminants (or so I reason) than should normally be entering your tank.
 
Used motor oil is often highly acidic from combustion byproducts. You cannot filter out the acidity or other chemical contamination, only gross particles. I'd expect damage to fuel lines, injectors, etc., etc., over time after adding it to gasoline. I wouldn't even add it to diesel fuel.
 
Is he trying to beat the fuel price by burning used motor oil?

You know some are running used cooking oil in diesel motors.
 
My thinking is also with the 'manufacturers' normal oil consumption' theory. '25 Rover suggests that -if convenient- to add ½ liters of engine oil for the first tankfull of gas for easing the break-in period. However that is 1925!

What benefit is aimed here? Better fuel lines, freeing up mechanical fuel pump? freeing up corrosion on the tank? Better cylinder lubricity? I wouldn't add used oil to tank at any cost though. May be some cheap fresh two stroke oil (for better mixing) at half the concentration at most. I experienced ¼ liter per tank (16 gals) which resulted in very slightly better revving (like would after an oil change).
 
Bad idea in a gasoline engine. Period.

Just setting aside the pollution control part and the acidity of used oil part, oil is an octane reducer.

If it's UCL you are after (and I believe there are some benifits) - I would look at some aftermarket additives, even ashless 2-stroke oil as mentioned, would be a better choice than used motor oil in your gasoline tank.
 
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