Diesel Performance Additives

A comprehensive look by a chemical engineer on additives that work and ones that probably don’t.


We think of ourselves as sailors, but we all depend on reliable power to propel us in and out of harbor, through calms and often to assist in storms. A good diesel can provide 10,000 hours or more of faithful power, but this depends, more than anything, on good clean fuel of the right spec. Can additives help? Yes … and at the same time not with everything. They claim to improve lubricity, increase cetane, kill bugs, reduce corrosion, eliminate water and reduce sludge. Some of this can be true and as often it isn’t. They can’t fix engine problems. They are no substitute for good fuel storage practices. But they can bridge minor gaps in fuel quality and are an important part of any fuel management program.

To continue reading this article or issue you must be a paid subscriber.

Subscribe to Practical Sailor

Get the next year of Practical Sailor for just $34. And access all of our online content - over 4,000 articles - free of charge.
Subscribe today and save 42%. It's like getting 5 months FREE!
Already Subscribed?
| Forgot your password? | Activate Web Access
Drew Frye
Drew Frye, Practical Sailor’s technical editor, has used his background in chemistry and engineering to help guide Practical Sailor toward some of the most important topics covered during the past 10 years. His in-depth reporting on everything from anchors to safety tethers to fuel additives have netted multiple awards from Boating Writers International. With more than three decades of experience as a refinery engineer and a sailor, he has a knack for discovering money-saving “home-brew” products or “hacks” that make boating affordable for almost anyone. He has conducted dozens of tests for Practical Sailor and published over 200 articles on sailing equipment. His rigorous testing has prompted the improvement and introduction of several marine products that might not exist without his input. His book “Rigging Modern Anchors” has won wide praise for introducing the use of modern materials and novel techniques to solve an array of anchoring challenges. 


  1. Al Halpern,
    For years I have been using a product called Marine Dee-Zol by Bell performance. This stuff was highly recommended by my diesel mechanic and seems to work on keeping the tank clean and eliminating most of the exhaust smoke. I was suppressed to not see it discussed in the recent article and was just wondering why.

  2. Re. Shelf life. The advice we have received on biocides and additives in general is that 2-3 years opened and 10 years unopened is OK. This squares with our experience; we’ve re-tested opened bottles stored in cool locations as old as 15 years and noted only minimal changes. So if it takes you a few seasons to use it up, that’s fine.