OK to pour used motor oil in my fuel tank?

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Kaboomba

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I figure if I can get away with it without shortening the life of the car, I'll be ahead by

1. Disposing of used oil in a convenient way
2. More miles for my fuel dollar
3. Slightly better power
4. Offset effects of E10 in my ol' Buick

Assume that

A. The oil is not totally chemically spent, i.e. I changed it before TBN was below 1

B. Oil has insolubles that are far smaller than the fuel filter can catch (insolubles smaller than 20 micron), because a nifty Amsoil EaO23 filter is being used

C. Oil is added to fuel at a rate of 1qt/10gal or less, in general

Am I scaring anybody yet???
crackmeup2.gif
 
You may only be ahead on item 1. You are assuming that the used motor oil adds a quantifiable calorific value to the fuel you are burning. Since the flash point of oil is much higher than petrol, you will probably be wasting some energy just trying to get it to ignite in the combustion chamber.

At a rate of 1 qt per 10 gallons, assuming your vehicle gets 30mpg, you are burning 1 qt every 300 miles, or 3 plus quarts every 1000 miles. Your O2 sensors and catalytic converter won't be too happy with that.
 
pour away, it's only $$$, besides, then you can stuff a really big engine in that Buick when it blows
crazy.gif
 
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Oil is low octane so if you get knock retard you won't be running as efficiently.

However you might be able to get by on less than 87 in winter with low ambient air temps.
 
id brave it in my lawn mower, but ask yourself this.....how clean do you believe your drain/catcher is? i know for me my catch can sits outside, hard telling what debris is in there. otherwise id just consider a small amount an upper cylinder lube
 
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Originally Posted By: Kaboomba
I figure if I can get away with it without shortening the life of the car, I'll be ahead by

1. Disposing of used oil in a convenient way
2. More miles for my fuel dollar
3. Slightly better power
4. Offset effects of E10 in my ol' Buick

Assume that

A. The oil is not totally chemically spent, i.e. I changed it before TBN was below 1

B. Oil has insolubles that are far smaller than the fuel filter can catch (insolubles smaller than 20 micron), because a nifty Amsoil EaO23 filter is being used

C. Oil is added to fuel at a rate of 1qt/10gal or less, in general

Am I scaring anybody yet???
crackmeup2.gif



Well the Buick is 16 years old - if its that near the end of its useful service life, it'd be a very unconventional way to end it.

-Spyder
 
Originally Posted By: tom slick
go for it! ignore the naysayers! report back what happens.


Thanks!

Originally Posted By: Steve S
I wouldn't do it in a gasoline engine .


What? Haven't you ever dumped your 2-cycle mix into your garden tractor by accident? Yep, the ole mower don't care none, either. And what about brother Billy Bob's '83 Skylark? That ole thing uses a quart per thousan as it is, and don't care none 't'all.

An for cryin out loud, my ol Buick uses 1qt/4000mi as it is, and has for the last 80K miles. I don't think doubling or tripling the rate will hurt anything.

Originally Posted By: crosseyedwx
NO! If your vehicles were diesels, you could get away with it (although it's highly illegal for on-road vehicles) by mixing it in with diesel fuel.


Hot dawg, I'm gonna have me a police chase! My Buick can dust those Crown Vics. Especially when I'm runnin OIL!

Originally Posted By: sunfire
Phos is not good for your cat.


My car has 107K on it and is pre-'96, and I have never had to pass emissions, and likely never will.

Originally Posted By: dwcopple
pour away, it's only $$$, besides, then you can stuff a really big engine in that Buick when it blows
crazy.gif



I assure you, this ole Buick can handle a H--- of a lot more than a little ole dollop of oil in the gas. It works fine on Hooch10 (E10), why not GoodStuff02?
 
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If you filter it well you may only damage your O2 sensor, fuel metering for carb or what ever your engine uses, and foul sparkplugs.

If you do not filter it well you could also damage your fuel filter, and or fuel pump.
 
Originally Posted By: chrome

At a rate of 1 qt per 10 gallons, assuming your vehicle gets 30mpg, you are burning 1 qt every 300 miles, or 3 plus quarts every 1000 miles. Your O2 sensors and catalytic converter won't be too happy with that.


The figure I actually had in my head for giving this a try was 1/2-quart per 14-gallon fill-up, which is 1:112 ratio.

I will probably just start real low and work up while monitoring MPG's.

Heck, if a car can handle 5.25oz of Lucas UCL, why not 8oz of lightly-used motor-oil?
 
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My Saturn burned oil at a rate of 700 miles/quart to (in the end) 250-300 mi/qt. Never did it foul a plug, damage an O2 sensor or foul the cat enough to throw a code.

What it may do to your fuel pump screen, fuel filter and fuel injectors may be another story.
 
Originally Posted By: Virtuoso
My Saturn burned oil at a rate of 700 miles/quart to (in the end) 250-300 mi/qt. Never did it foul a plug, damage an O2 sensor or foul the cat enough to throw a code.

What it may do to your fuel pump screen, fuel filter and fuel injectors may be another story.


Agreed. From a combustion standpoint, I doubt you'd notice that added oil as 'blue smoke', nor would it effect your performance or emissions system on a vehicle of that vintage. Long term effects on the fuel system? That's anyone's guess.

Joel
 
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