Jeff, Jon, Ben - interesting subject. Diesel contamination generally takes three forms - biological (bacteria and molds), inorganic ( grit, clay, sand or dirt known collectively as asphaltene), and water. You would be amazed where the water can come from, including the refining process, particularly associated with ultra-low-sulphur fuels.The more sophisticated our engines become (electronic, high pressure fuel injection, etc), the more critical this issue becomes.

Fuel filtration and fuel polishing are related but measurably different. The issue is not just clean fuel and the impact it has on injectors and the engine itself, but fuel tank corrosion from the sludge/water in the bottom, and a host of new issues regarding bio blended diesel as well.

We have just published a comprehensive tech article intitled "Fuel Filtration...the key to engine reliability". You will find it in the February issue of Passage Maker Magazine (in the boating section of your favorite book store), or log on to our website at Zimmermancoach.com, fill out the contact form, request a copy, and we will mail it to you.