ATF, 2 Stroke, or Power Steering Fluid for Diesel Additive?

Using an 'alternative product' is an idea that has been around for a long time, but it raises the question, “Does it really help?”

Many people find the quality of diesel fuel questionable, even when fueling at their station of choice. At Opti-Lube we occasionally meet people who have questionable ideas about adding 'alternative products' such as ATF, Power Steering Fluid, 2-Cycle Engine Oil and even used motor oil to their diesel in the hopes of adding lubrication. Using an 'alternative product' (as opposed to name brand additives) is an idea that has certainly been around a long time, but does it really help? We’ve taken the time to research independent studies in addressing this question. Let’s look at 3 popular ‘alternatives’.


A technical study conducted by ‘The Fuel Expert’ states: Regarding the use of ATF, Diamond Diesel interestingly states on their website:  “The results of the study support a view that the practice of dosing diesel with 2-stroke oil is surprisingly ineffective in terms of lubricity and cetane improvements. Engine performance, fuel consumption and emissions were also unchanged; however the use of 2-stroke oil in diesel is potentially harmful to modern diesel injection equipment. Trace amounts of zinc, an element which is found in most 2-stroke oils, are well known to cause injector nozzle fouling and the study measured high levels of  injector fouling when the test engine was running on diesel dosed with 2-stroke oil."



Regarding the use of ATF, Diamond Diesel interestingly states on their website:

“It is not a good practice and likely will cause far more problems than it could solve. Using ATF in this way is something of an “old truckers tale” and has been used on everything from Volkswagens to Class 8 trucks. Another erroneous strategy is to add old or new engine oil for lubricity. The problem with these “additives” is they are specifically designed to resist high temperatures and burning. As a result, if they are added to diesel fuel they leave behind ash, heavy metals, and other deposits that can easily cause costly damage to fuel injectors and other sensitive engine components.”



That brings us to Power-Steering Fluid. It seems like it would add lubricity to just about anything, right? When being used as fuel additives Power-Steering Fluid and ATF have a lot of similarities. ATF and Power-Steering Fluid have a high combustion point which negatively affects diesel fuels’ efficiency. Diesel fuel alone will burn sooner and longer than diesel treated with power-steering fluid. Since Power-Steering Fluid, ATF, and Motor Oils are not designed to be burned they do not vaporize as well as diesel fuel.


The use of 'alternative products' calls into question dosing, and specifically: What dosage provides the most benefit? And how does the cost compare to brand name diesel additives? Despite all the speculation you will find online, there are no tests that provide a clear answer. And without dosage qualifiers there is no way to compare the cost. However, considering Opti-Lube Summer+ is only 2-3 cents per treated gallon of diesel fuel, you might ask yourself, is it really more cost effective to use one of these harmful 'alternatives'?


Additive companies and fuel outlets (including Opti-Lube) have done extensive research proving that cetane chemicals speed up the combustion point of diesel fuel for increased performance. The cited studies show that cetane improvement of these 'alternate products' were negligible.

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