removing two fill plugs (2). Replace plugs after oil has
been replenished.
c. Draining.
(1) Close drain plugs (3, fig. 3-1).
(2) Remove the two oil lines from adapter.
(3) Place container under drain plugs;
remove fill plugs; cover opening in tank to prevent dirt
entering, then open drain plugs.
(4) When oil is drained, close drain plugs,
then install oil lines on adapters.
(5) Remove covering placed over fill holes,
fill tank with required quantity of proper oil (LO 5-3810-
206-12).
(6) Open drain plugs and allow oil to enter
lines to hydraulic cylinders; add more oil in tank, if
necessary; then install fill plugs.
3-19. Radiator Service
a. Maintaining Water Level. Remove radiator cap,
add water until it stands two inches below filler neck,
then install radiator cap.
b. Draining, Cleaning, Flushing, Neutralizing, and
Filling. Refer to TB ORD 651 (Use of Antifreeze
Solutions and Cleaning Compounds in Engine Cooling
Systems) for instructions on cleaning, flushing, and
neutralizing radiator. Drain and refill as described
below.
(1) Remove radiator cap, then open
draincocks on radiator and engine block.
(2) When engine and radiator is fully drained,
close all draincocks.
(3) Fill system with clean water until it stands
two inches below the filler neck. Install radiator cap.
3-20. Fan Drive Belt Adjustment
a. On Engine Model 687C-18-ES.
(1) Loosen four capscrews (view A, fig. 3-16)
and locknut.
(2) Increase belt tension by turning setscrew
clockwise.
Loosen belt by turning setscrew
counterclockwise.
Figure 3-16. Fan drive belt adjustment (sheet 1 of 2).
Note.
(2) Loosen locknut on adjusting screw and
Proper adjustment will allow belt to
turn adjusting screw clockwise until the two belts can be
depress from 3/4 to one inch at a
depressed approximately 1/2 inch midway between
point midway between pulleys, while
pulleys with a force of approximately 25 pounds.
using a moderate pressure.
(3) When adjustment is correct, tighten the
two bracket retaining bolts and locknut.
Recheck
(3) When proper adjustment is attained,
adjustment.
tighten the four capscrews and locknut.
Note.
b. On Engine Model DSSSTA.
Fan drive belts must be replaced in
(1) Loosen the two bracket retaining bolts
matched sets. When belts can be
which hold idler hub bracket to timing hear cover (view
depressed 3/4 inch midway between
B, fig. 3-16).
pulleys, adjustment is required.
3-28
