Fuel Tank Fill Cap - Fuel Tank Noise/Gauge Inaccurate
File in Section: 6E - Engine Fuel & EmissionBulletin No.: 56-63-04
Date: August, 1995
Subject:
Fuel Tank Noise, Fuel Gage Inaccurate, Reduced Fuel Capacity (Replace Fuel Tank Fill Cap)
Models:
1992-95 Chevrolet and GMC Truck C/K Models
with 6.5L Diesel Engines (VINs F, S - RPOs L56, L65)
CONDITION
Some owners of the above models which operate in very dusty environments may comment on any of the following conditions: A noise emanating at the fuel tank which may be the sound of the fuel tank "oil canning"; Reduced fuel tank capacity; Inaccurate fuel gauge readings.
CAUSE
The fuel tank fill cap vent may become clogged with dirt on some diesel models operating in very dusty environments. The clogged fill cap vent may restrict the fuel tank from properly ventilating. A negative pressure may develop in the fuel tank, causing the fuel tank to "oil can" and possibly collapse inward.
CORRECTION
A redesigned fuel tank fill cap is available. The new fill cap has a filter which will significantly reduce the possibility of clogging. As part of regular maintenance, the fuel tank fill cap should be replaced every 25,000 miles on diesel equipped trucks operating in very dusty environments.
PARTS AND WARRANTY INFORMATION