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I thought I posted this already, but I can't seem to find answers...so here we go...

Several years ago, I obtained a bunch of new motor oil at a local store when they were closing cases out for 57 cents.

I don't need it any more and wondering if I can just dump a quart or two in my tank when I fuel up. My truck is in great shape and I don't want to screw up the fuel system, but i'd like to burn the oil if I could.

Any input is appreciated.
 

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No.

This is not good for your 7.3 PSD.

Nor is this a good method to dispose of brand new motor oil that you no longer want.

Give it to someone who will use it for its intended purpose.

57 cents a case? By any chance are the quart containers round and cardboard with metal end caps?
 

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Discussion Starter · #3 ·
Nope. They're in the plastic bottles. Not sure why its bad for the fuel system but better safe than sorry. I guess i will not pour it in the tank...
 

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I'm not sure why it would be bad. A lot of us experimented with burning used oil. We found that a mix of 85% oil and 15% old gasoline worked best. My truck burned several hundred gallons of waste motor oil with no issues. My supply finally dried up so I abandoned the effort. Adding the oil to your tank won't help anything, but it won't hurt either.


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Lots of owners run motor oil in their 7.3's with no problems. There are even those that run old filtered oil in their engines with no problems.

A quart or two in a full tank won't hurt a bit in a 7.3, don't try it in a 6.0, 6.4, or a 6.7.
 

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I can think of 100 better uses to get rid of perfectly good motor oil than burning it up in a diesel.

What about the various additives? What happens to those in the combustion process? Aren't they just going to foul injectors, etc?
Plus some 7.3's have a Cat don't they? Plus the concern of additional wax and parafin in cold temperatures.

But I am scratching my head trying to think why it would be an advantage to use it in this manner?
 

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It is always best to use a product for it designed and intended purpose and I agree that either using it or selling it to someone might be best, but it won't hurt a 7.3.

As for the cats on these trucks that have them, it really isn't a catalytic converter like they have on a gas vehicle. It is just a housing with a honeycomb inside of it that I think is more to catch soot than it is to do anything else. There isn't even a sensor on it for the PCM to monitor what is going on with it.
 

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Well, I guess you guys know more about it than me but I still wonder if the oil additives are good for injector coking and I am pretty certain that the exhaust produced is going to be pretty darned toxic to the environment. I am not what you would call a tree hugger but I am not someone looking to add extra pollution to my kid's air for no reason either.
 

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This is what my concern would be adding motor oil. It increases viscosity of diesel fuel, it has low volatility and it introduces metal contamination. Plus it is not additized and the damage that untreated diesel fuel causes in engines is well documented.

"Fouling due to solid deposits inside a diesel fuel injector or its nozzle is an important problem experienced with diesel fuel injectors. This phenomenon arises during injector aging and consists of a series of chemical reactions whose products are deposited on the external and/or internal metallic surfaces of the injector and/or nozzle. Diesel injector fouling deposits can be broadly categorized as injector nozzle deposits and internal diesel injector deposits (IDID). The latter are also referred to as internal injector deposits (IID)....

Properties and Chemical Composition of the Fuel. Fuel characteristics such as high viscosity, low volatility and reactivity of the unsaturated hydrocarbon chains (olefins, aromatics), can facilitate carbon deposits at the nozzle holes and the formation of protuberances on the injector nozzle tip. The presence of small traces of Na, Zn, Cu, and Ca in the fuel (metal contamination) has been demonstrated to significantly intensify nozzle fouling as well as internal injector deposits [Caprotti 2005][Tang 2009]. The additive package dispersed in the fuel also has an important effect on metal contamination and more generally on injector coking."

https://www.dieselnet.com/tech/engine_fi_nozzle_deposits.php

And here is another study which determined trace amounts of Zinc accelerated injector coking:

"The physical origin of injector coking in diesel engines was clarified and the most critical design parameters and operating variables for the occurrence of the phenomenon were identified. Injector fouling was shown to be affected by many factors, such as injector temperature, nozzle configuration, hole diameter and conicity, fuel composition. In particular, minute quantities of Zn, which can be added to the fuel, were verified to sensibly catalyze the growth of the undesired deposits."

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1634211
 

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No doubt there are metals present that aren't in diesel. Especially in waste motor oil. While there are a few studies out there, there are hundreds of millions of hours of oil burners burning oil out there. Transoceanic vessels often time run exclusively on waste oil. A lot of on site drilling equipment runs on waste oil. In fact, I read a few articles about some machinery that they were running straight crude oil in. As to viscosity changes, adding two quarts of C30 chain petroleum to a 20+ gallon tank of C18 chain fuel isn't going to affect much. Probably less than the difference in viscosity change between 80° fuel and 90° fuel.

Still, if it was me and I'd just scored cases of new motor oil, I'd use it on oil changes - lawnmowers, gassers - even give it to a local men's group at church that does free oil changes for little old ladies...
 

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Good info RT.
Thanks
 
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