Q: Why do so many diesel engine OEMs not recommend the use of diesel fuel additives?
A: If you consult your owner’s manual, many times you will read that the OEM does not recommend the use of supplemental diesel fuel additives. The most common theme between all manuals speaks to emulsifiers in the fuel additive. OEMs do not recommend products that contain emulsifiers because the fuel additive will grab hold of any water found in the fuel tank or system and carry it to the engine to be burnt. Most diesel applications have a fuel water separator in the fuel system to remove water. Emulsifiers will hold onto that water and render the fuel water separator ineffective. OEMs have found water reaching the fuel pump and injectors to be very damaging. Under high heat and pressure, that water can cause corrosion and steam in the system, which could lead to failure of the fuel system components. For that reason, OEMs have made blanket statements that you should not use diesel fuel additives.
Now, for example, if you take Amsoil's Diesel Injector Clean that contains a demulsifier that promotes the separation of water from fuel making the fuel water separator more effective, this fuel additive would comply with any concerns of the OEM. It is ultimately important to understand the perspective of the OEM before you choose a diesel fuel additive. This way you can feel comfortable knowing your fuel additive of choice will comply with the concerns of the OEM.
Information provided by: Amsoil
