Originally Posted By: SVTCobra
There is a diesel/water seperator employed on many diesel engines, but I think you may have your emulsifier term mixed up. Fuel additives uses a demulsifier to break up the water into little tiny droplets so they can pass through the engine. An emulsifier would bind the water and diesel together which may cause additional wear to the engine/injectors because the water is not broken into little droplets but can come through in large amounts.
Quite the opposite. This was covered ad nauseum on TDIClub and ensuring terminology was correct was a big part of the discussion..
An emulsifier takes any free water, disperses it into microscopic droplets and binds it with the fuel. This means it can be sent through the fuel filter bound together & into the engine and 'burned' along with the fuel. Think of how mayonnaise is a smooth, consistent emulsion of oil & water that does not separate into its components.
A De-emulsifier (coalescing) additive forces free water away from fuel so it will pass through the fuel system in discrete, visible droplets and be caught in the fuel filter/water separator. Think of oil & vinegar salad dressing - even if you shake it up, you have small globules of each mixed together. Once it sits for a few minutes, they separate out into distinct layers according to density.
My Golf has been retrofitted to use the Cat 1R-0750 fuel filter which does not have a water drain, so I use emulsifying fuel additives (Howes Diesel Treat, Power Service) in lieu of coalescing fuel additives (Stanadyne, etc...). The stock filter (equipped with a water drain) was not easy to drain, had no sensing capability for when it had accumulated water and was not an effective water blocking filter in the first place.
The
one time I had water in fuel no amount of additive would have helped.