# Diesel Fuel Tank Cleaning in Upland > Water, sludge or algae in your diesel tank? Route 66 Auto Repair in Upland drains and cleans diesel fuel tanks and shows you what came out. Source: https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-tank-cleaning Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** If your filters keep clogging, look at the tank. We **drain and clean it**, and **show you the sample** so you can see why. Diesel fuel tank cleaning removes water, sediment and microbial sludge that clog filters and wear injectors. Route 66 Auto Repair in Upland drains and cleans diesel tanks on pickups and vans, often after a bad fuel fill or after a truck sat for months. We show you a sample of what came out, and our ASE-certified technicians explain in writing whether the tank can be cleaned or should be replaced. ## What are the signs of a dirty diesel tank? - Fuel filters clogging long before their interval - Water-in-fuel light coming on repeatedly - Black, slimy residue in the filter or separator bowl - Power loss that gets worse as the tank gets low - Truck that sat for a season before the trouble started ## What grows in diesel fuel? Diesel absorbs water, and water collects at the bottom of the tank. Microbes live where the fuel and water meet, forming a dark mat that breaks off and plugs filters. Warm Inland Empire days speed that up. Additives can slow new growth, but they do not remove a thick layer that is already there. That takes draining and physical cleaning. If you are not sure the tank is the source, a [diesel fuel system contamination test](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-system-contamination-test) comes first. ## Our diesel fuel tank cleaning process 1. **Sample the bottom:** Fuel is drawn from the lowest point so you can see any water or sludge. 2. **Drain and remove:** The tank is drained into approved containers and lowered if the cleaning needs it. 3. **Clean and inspect:** The tank interior is cleaned and inspected, along with the pickup screen and sending unit. 4. **Refit and replace filters:** The tank goes back in, filters are replaced, the system is primed, and the truck is road tested. ## What's included in diesel fuel tank cleaning - Bottom sample in a clear container - Tank drain and disposal of contaminated fuel - Interior cleaning and pickup screen inspection - Fuel filter and separator service - System prime and road test - Photos of the tank interior when accessible ## Is it a need-now or need-later repair? **Need now:** - Water-in-fuel light plus stalling - Filters plugging within days **Need later:** - A light haze in the separator bowl after a single bad fill - A truck that is about to sit for a long stretch ## How pricing and timing work Tank size, whether it must be dropped, and how much fuel is in it affect labor. A tank with rust or a failed liner may be cheaper to replace than to clean, and [diesel fuel tank repair](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-tank-repair) covers that choice. We state the fee at the counter before testing, and every line is on the written estimate. ## Aftercare Fill from busy stations and keep the tank fuller when the truck will sit. Drain the water separator as your manual says. A follow-up [diesel fuel filter replacement](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-filter-replacement) shortly after cleaning catches leftover debris. ## Frequently asked questions ### Can additives clean the tank for me? They help prevent growth and can deal with small amounts of water. They will not remove sludge that has built up. That needs draining and cleaning. ### Will you save my fuel? If the fuel tests clean above the contaminated layer, we discuss options. Heavily contaminated fuel is disposed of properly. ### Could dirty fuel have hurt my injectors? Possibly. If the truck ran rough, we recommend checking injectors after the tank is clean so you know where you stand. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.