# Fuel Tank Service and Cleaning in Upland > Fuel tank service in Upland for contaminated fuel, water, rust, bad gas and fuel gauge problems. We drain, inspect and clean with a written estimate first. Source: https://route66autorepairshop.com/engine-services/fuel-tank-service 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:** **Fuel tank service** handles **contaminated or stale fuel**, wrong-fuel mistakes and **sending unit** faults, so debris does not reach your pump and injectors. Fuel tank service deals with what is inside the tank: stale gas from a car that sat for months, water or rust, debris, the wrong fuel pumped in, or a fuel gauge that reads wrong because of the sending unit. Route 66 Auto Repair in Upland drains and inspects the tank, cleans or replaces what is contaminated, and protects the pump and injectors downstream. You get a written estimate before work starts. ## When does a fuel tank need service? - A car, truck or classic that sat for months with fuel in it - Diesel pumped into a gas car, or gas into a diesel - Water or rust found in a fuel filter - Sputtering that started right after a fill-up - A fuel gauge that sticks, jumps or reads empty when full - Varnish smell from the filler on a stored vehicle ## What should you do if you put the wrong fuel in? Do not start the engine. If it is already running, shut it off as soon as it is safe. The less the wrong fuel circulates, the smaller the job. Call us and arrange a tow-in rather than driving over. Once the car is here, we drain the tank, flush the lines, replace the filter and check how far the fuel traveled. If the engine ran on it, we check for misfires and injector trouble before sending it home. ## Our fuel tank service process 1. **Sample the fuel:** We draw a sample into a clear container so you can see the water, rust or color. 2. **Drain and access:** The tank is drained into approved containers and the pump module is accessed or the tank lowered. 3. **Clean and inspect:** We clean out sediment, inspect the pump strainer and sending unit, and photograph the inside when we can see it. 4. **Replace contaminated parts:** Filters, strainers or the sending unit are replaced as quoted, and lines are flushed where needed. 5. **Refill and verify:** Fresh fuel goes in, we check pressure and gauge readings, and we road test. ## What's included in fuel tank service - Fuel sample in a clear container - Tank drain and approved disposal - Sediment cleaning and pump strainer check - Sending unit and fuel gauge test - Fuel filter replacement as quoted - Pressure check and road test ## Need-now or need-later? **Need now:** - Wrong fuel in the tank - Water in the fuel with stalling or misfires **Need later:** - A gauge that reads a little low but moves - Old fuel in a stored vehicle you are not driving yet ## How pricing and timing work The work depends on how the tank is accessed. Some cars have a service port under the rear seat, while others require lowering the tank. Fuel disposal and the number of parts that were contaminated also change the total. Phone quotes are ranges until we sample the fuel. AAA members get 10% off parts and labor, up to $75. Tow-ins and after-hours key drop are available. ## Aftercare Run the next tank or two from a busy station. If the car will sit again, ask us about storing it with a full tank to limit condensation. Stored classics often need more than fuel, and our [general auto repair](https://route66autorepairshop.com/auto-repair-services) team can check the brakes, tires and belts too. If a leak shows up instead, see [fuel tank repair](https://route66autorepairshop.com/engine-services/fuel-tank-repair). Persistent stumbling after service may call for [fuel injector cleaning](https://route66autorepairshop.com/engine-services/fuel-injector-cleaning). ## Frequently asked questions ### How do I know if my gas has gone bad? Old gas smells sour or like varnish and may look darker than fresh fuel. The engine may crank long, run rough or stall. We sample it so you can see it before any work is approved. ### Why is my fuel gauge wrong? Most often the sending unit inside the tank is worn or corroded. Sometimes the wiring or the gauge itself is at fault. We test the sender's signal before replacing it, and our [electrical system diagnostics](https://route66autorepairshop.com/electrical-services/electrical-system-diagnostics) team handles wiring faults. ### Do fuel additives clean the tank? Additives can help with light deposits and stabilize fuel for storage. They cannot remove water, rust flakes or sediment. Those need to be drained out. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.