Fuel Water Separator Filter

Doc's Diesel Fuel/Water Separator Filters

Diesel and Water Don't Mix. Now They Don't Have To.

Water is diesel fuel's oldest enemy—it sneaks in through condensation, bad station tanks, and humid air, then goes to work corroding steel fuel components, feeding microbial growth, and flashing to steam against injector tips that cost four figures a set. Your fuel/water separator is the checkpoint that stops it, and it only works if it's fresh. Doc's Fuel/Water Separators pull water out and strip dirt, rust, and debris at the same time, protecting the most expensive plumbing on your truck.

Built to Catch What Fuel Carries.

Premium 3-layer pleated cellulose glass media delivers fine filtration without choking flow, large-capacity pleats keep flow rates strong deep into the filter's life, high-strength carbon steel housings stand up to fuel system pressures (when applicable), and every filter arrives ready to install with the o-rings your application needs.

Built to OEM Specs. Backed by the Doc's Fitment Guarantee.

Every separator meets or exceeds OEM design, fit, and function and carries the Fitment Guarantee: if it doesn't fit your truck, we'll make it right. No guesswork. No BS.

Doc's Makes It Easy.

Find yours with the Vehicle Selection Tool and change it every 5,000 to 10,000 miles, 15,000 maximum—sooner in humid climates or if your fuel sources are hit-or-miss. Many trucks run a separator alongside a fuel filter; our Filter Sets cover both in one order.

Free Shipping on All U.S. Orders $99+

Stock a spare with your next order and everything over $99 ships free anywhere in the U.S. Diesel and water don't mix. With a fresh separator, they never have to.