Fuel Tank
An automotive
fuel tank must safely hold an adequate supply of fuel for prolonged engine operation. The
location of the fuel tank (fig. 4-2) should be in
an area that is protected from flying debris, shielded from collision damage, and one that
is not subject to bottoming. A fuel tank can be located just about anywhere in the vehicle
that meets these requirements.
Figure 4-3 shows the
general construction of a fuel tank used on automotive equipment. Fuel tanks are usually
made of thin sheet metal or plastic. The main body of a metal tank is made by soldering or
welding two formed pieces of sheet metal together. Other parts (filer neck, fuel tank cap,
and baffles) are added to the form to complete the fuel tank assembly. A lead-tin alloy is
normally plated to the sheet metal to prevent the tank from rusting.
The fuel tank
filler neck is an extension on the tank for filling the tank with fuel. The filler cap
fits on the end of the filler neck. The neck extends from the tank through the body of the
vehicle. A flexible hose is normally used as part of the filler neck to allow for tank
vibration without breakage.
In vehicles
requiring unleaded fuel, a fuel neck restrictor is used inside the filler neck. This
prevents the accidental use of leaded gasoline in an engine designed for unleaded. The
restrictor is too small to accept the larger leaded fuel type pump nozzle.
WARNING
If the restrictor is
removed and leaded fuel is used in a vehicle designed for unleaded fuel, the catalytic
converter will be damaged. This action is a violation of federal law; therefore, NEVER
remove the filler neck restrictor.
Modern fuel
tank caps are sealed to prevent escape of fuel and fuel vapors (emissions) from the tank.
The cap has pressure and vacuum valves that only open under abnormal conditions of high
pressure or vacuum.
Fuel tank
baffles are placed inside the tank to prevent the fuel from sloshing or splashing around
in the tank. The baffles are metal plates that restrict fuel movement when the vehicle
accelerates, decelerates, or turns corners.
Fuel tanks
give little or no trouble, and generally require no servicing other than an occasional
draining and cleaning.
WARNING
If a fuel tank is punctured or develops
leaks, it should NOT be welded or repaired with or near an open flame until all traces of
fuel and fuel vapors have been completely removed from the tank. Before attempting to make
any repairs to a fuel tank, consult with the shop supervisor for specific instructions on
all safety precautions to be observed.
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