Service Manual User Manual

Section 8B
8B-12
Inform the owner/operator of the vehicle to use No. 2 D
diesel fuel, unless ambient temperatures are below 32° F
(0° C). When temperatures are below 32° F (0° C), a
blend of No. 1 D and No. 2 D fuels (known as "winterized"
No. 2 D) may be used.
Note: No. 1 D fuel may be used, however, fuel economy
will be reduced.
Use a low-sulfur content fuel with a cloud point (the tem-
perature at which wax crystals form in diesel fuel) at least
10° below the lowest expected fuel temperature. The vis-
cosity of the fuel
must
be kept above 1.3 centistrokes to
provide adequate fuel system lubrication.
Note: When using diesel fuel with a sulfur content below
1.3 percent, the filter change interval must be reduced by
75 hours. The use of fuel with a sulfur content above 1.3
percent is not recommended.
8B.7.2 Fuel Tank
The fuel tank (item 24, Fig. 8B–7) is located directly
beneath the operator’s cab.
A. Removal
The operator’s cab must be partially removed in order to
remove the fuel tank. Follow the directions for removing
the operator’s cab in
Section 4 Cab, Covers and Mirrors
,
then remove the fuel tank. If a leaking fuel tank is sus-
pected, check that all fuel tank inlets and outlets are not
the cause of the leak before removing the cab and the
fuel tank from the vehicle.
B. Disassembly
1. Remove the four #10-24 x 3/4" pan-head screws
(item 12, 8B–7), the #10-24 x 5/8" pan-head screw
(13), and the five #10 lockwashers (11) securing the
fuel sender cover (10) and fuel sender with gasket (9)
to the fuel tank.
2. Remove the black MI #6P square-head plug (8), the
#6-6P hose barb coupling (7), the #5-6P 90° hose
barb elbow (28) and both #10-6P 90° hose barb
elbows (25).
C. Cleaning and Drying
If contaminated fuel or foreign material is in the tank, the
tank can usually be cleaned. Replace a leaking or dam-
aged tank. DO NOT attempt to repair, plug or patch a
leaking or damaged fuel tank. The tank is manufactured
using an injection molding process and cannot be
repaired.
To clean the fuel tank:
1. Have a dry chemical (Class B) fire extinguisher near
the work area.
2. Invert and tilt the tank from side to side. Safely drain
any fuel into a suitable container. Dispose of properly.
3. Clean the fuel tank with a high-pressure washer, or
flush the tank with hot water for five minutes. Invert
the tank, tilt it from side to side, and drain the water.
4. If necessary, add a diesel fuel emulsifying agent to
the tank. Refer to the manufacturer’s instructions for
the correct emulsifying agent-to-water mixture ratio.
Refill the tank with water, and agitate the mixture for
10 minutes. Drain the tank completely.
5. Refill the fuel tank with water until it overflows.
Completely flush the tank with water. Empty the tank
and allow it to dry completely.
D. Inspection
1. Inspect the fuel tank thoroughly for any cracks, slices,
leaks or other damage. Replace a leaking or
damaged tank. DO NOT attempt to repair, plug or
patch a leaking or damaged fuel tank. The tank is
manufactured using an injection molding process and
cannot be repaired.
2. With the fuel tank removed from the vehicle, plug all
openings except one elbow fitting. Install the elbow
fitting and apply approximately 1 to 1-1/2 psi (7 to 10
kPa) of air pressure through the elbow. Check the
tank for leaks by applying a soap solution to the
exterior of the tank, or by submerging the tank in
water and looking for bubbles to appear at the
cracked or damaged area.
E. Assembly and Replacement
1. Install the fuel sender with gasket (item 9, Fig. 8B–7)
and the fuel sender cover (10) to the fuel tank.
Secure with four #10-24 x 3/4" pan-head screws (12),
and four #10 lockwashers (11).
2. Coat threads with Teflon® (31) and install the black
MI #6P square-head plug (8), the #6-6P hose barb
coupling (7), the #5-6P 90° hose barb elbow (28) and
both #10-6P 90° hose barb elbows (25).
3. Replace the fuel tank in the cab mount subframe.
Attach the fuel level gauge wire to the #10-24 x 5/8"
pan-head screw (13), slide a #10 lockwasher (11)
onto the screw and secure the screw to the fuel tank
at the fuel sender cover.
WARNING: DO NOT mix gasoline or alcohol
with diesel fuel. The mixture can cause an
explosion.
WARNING: NEVER drain or store fuel in an
open container due to the possibility of explo-
sion or fire. Discard the fuel in an approved
manner.
Model 3606 • Origin 10/99