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.
1990 Chevrolet APVFACTORY OEM SERVICE PROCEDURE
Fuel System (Diesel): Water-In-Fuel
- Fuel filter should be drained every 5000 miles or when "WATER-IN-FUEL" warning light glows. Diesel fuel can damage asphalt and painted surfaces. Always place a drain pan under drain hose to collect fuel.
- Stop vehicle and turn engine off. Apply parking brake. Remove fuel tank cap. Open water drain valve 2-3 turns. Start and allow engine to idle for 2 minutes or until clear fuel is observed. Turn engine off and close water drain valve.
- Install fuel tank cap. If "WATER-IN-FUEL" warning light comes on after driving a short distance or if engine runs rough or stalls, a large amount of water may be present in fuel tank. Purge fuel system. See PURGING FUEL SYSTEM in ADJUSTMENTS in this article.
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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