Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 250 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING - 6.6L)FUEL SYSTEMSFUEL SYSTEM CLEANINGCLEANING WATER FROM FUEL SYSTEM
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Cleaning Water From Fuel System
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Cleaning Water From Fuel System
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect negative battery terminal.
- Drain fuel tank.
- Remove fuel tank.
- Remove fuel sending unit.
- Inspect fuel tank and fuel sender for rust, fungi or bacteria. If there is rust, replace rusted components.
- Clean inside of fuel tank and fuel sender with hot water.
- Use compressed air to dry fuel tank and fuel sender.
- Disconnect the ends of the fuel filter inlet line (both ends), transfer pump pressure line and suction line (if applicable), fuel filter outlet line (both ends), fuel filter drain and fuel return line (both ends).
- Inspect each of the pipes and lines.
- Replace any rusted pipes.
- Clean inside of fuel filter housing.
- Dry fuel filter housing with compressed air.
- Dry inside of each line with low pressure air.
- Remove ignition 1 relay from the underhood fuse/relay center.
- Install a new fuel filter.
- Install sending unit and fuel tank.
- Add clean diesel fuel to the primary tank until the tank is 1/4 full.
- Reconnect fuel filter inlet line, fuel filter outlet line, transfer pump pressure and suction (both ends) lines and fuel return line (tank end).
- Connect fuel filter drain to a line that flows into a clean metal container.
- Reconnect battery terminals.
- Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into a metal container.
- Close fuel filter drain and remove bleeder hose.
- Install a hose on the fuel return line near the glow plug relay, and insert other end into a 2-gallon metal container.
- Crank engine for 30 second time intervals, with one minute cool down periods. Continue until one gallon of fuel has passed into the container.
- Connect fuel return line.
- Install ignition 1 relay in the underhood fuse/relay center.
- Start and operate engine.
- Turn engine off.
- Clean any fuel spillage from engine.
- Fill fuel tank and add a biocide, if needed.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.