# Diesel Fuel Line Repair in Upland > Diesel fuel line repair in Upland for supply, return and high-pressure lines. Leaks, air intrusion and chafed lines fixed safely, with a written estimate. Source: https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-line-repair 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 lines can **leak or pull in air**. We find the damaged section and treat high-pressure lines with care because of the **injection injury risk**. Diesel fuel line repair at Route 66 Auto Repair in Upland covers the supply lines from the tank, the return lines back to it, and the high-pressure lines that feed the injectors. A cracked or chafed line can leak fuel, pull in air or both. Our ASE-certified technicians find the damaged section, replace it with the correct line and fittings, and prime the system, with a written estimate first. ## Which diesel fuel lines fail most often? Supply lines run along the frame and take road debris, heat and rubbing against brackets. A small crack there may never drip, but it can let the lift pump pull air, which causes rough running and long cranks. Return lines carry warm fuel back to the tank and can split at rubber sections or loose clips. High-pressure lines between the pump, rail and injectors carry fuel at extreme pressure. A leak there can spray a fine mist that can penetrate skin. Never run your hand along a running diesel to find a leak. If you smell fuel with the engine running, shut it off and call us. ## What are the signs of a diesel fuel line problem? - A strong diesel smell with the engine running - Wet spots along the frame rail or near the engine - Long cranking after the truck sits overnight - Rough running with no code or a low pressure code - A line rubbing through its protective sleeve ## Our fuel line repair process 1. **Locate safely:** Leaks are found with the engine off first, then carefully with approved methods if needed. 2. **Estimate:** The damaged section and the correct replacement line and fittings are listed in writing. 3. **Replace:** Lines are replaced and routed with new clips so they do not rub again. 4. **Prime and pressurize:** The system is primed and brought up to pressure. 5. **Leak check:** Connections are rechecked, and the truck is road tested. ## What's included in diesel fuel line repair - Leak and chafe inspection along the full line - Correct replacement line and fittings - New clips and protective sleeving where needed - System priming - Pressure and leak check after repair ## Is a fuel line repair need-now or need-later? **Need now:** - Any leak on the high-pressure side - Fuel dripping near exhaust or wiring - Air intrusion that causes stalling **Need later:** - A worn sleeve with an undamaged line underneath - A clip that has loosened without chafe ## How pricing and timing work A short supply section is usually a modest job. High-pressure lines on some engines sit under the intake, which adds labor. Some lines are specific to the engine and may need to be ordered. AAA members save 10% on parts and labor, up to $75. ## Aftercare Check for fuel smell the first few days. Injector feed lines are covered on [diesel fuel injector line repair](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-injector-line-repair), and leaks elsewhere on [diesel fuel system leak repair](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-system-leak-repair). If you want the pressure verified later, see [diesel fuel line pressure testing](https://route66autorepairshop.com/diesel-engine-services/diesel-fuel-line-pressure-testing). ## Frequently asked questions ### Can a fuel line leak without dripping? Yes. On the suction side, a small crack can pull air in instead of pushing fuel out. That shows up as rough running or hard starts. ### Can I patch a diesel fuel line with a hose clamp? It is not a safe long-term fix, and never on a high-pressure line. Replace the damaged section with the correct line. ### Why is a high-pressure fuel leak dangerous? The fuel can spray with enough force to penetrate skin, which is a medical emergency. Shut the engine off and let us find it. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.