plys before making tension adjustments. The fan drive
belts should be checked and adjusted after each 50 hours
of operation, or weekly.
4-55. New drive belts will stretch after the first few hours
of operation. After the first eight hours of operation,
check the belts again and retighten if necessary. Adjust
the belt tension so that a firm push with the thumb at a
point midway between the longest span deflects the belts
approximately 3/4 inch (2 cm). Adjust the belt tension as
a. Loosen the four capscrews (2 on each side of engine)
securing the fan bracket to its mounting blocks. Also
loosen the four capscrews securing the fan shroud to the
b. If the belts are too tight, push the fan bracket
downward to loosen the belts. If the belts are too loose,
use a pry bar (between the stud welded on the inside of
mounting bracket and the mounting block) to move the
CAUTION: When adjusting the fan pulley, always adjust
the fan shroud the same distance in either
direction. The fan must always be centered
in the shroud.
c. When the correct adjustment is obtained, tighten the
four fan bracket capscrews securely. Tighten the four fan
CAUTION: Before starting the engine, make sure that fan
blade tips do not contact the shroud.
NOTE: Replace the two drive belts as a matched set
when one is worn. Single belts of similar size shout De
FIGURE 4-21. LUBRICATING THROTTLE AND
uses as a substitute for a matched belt set. Premature
belt wear can result because of belt length variations after
short periods of operation.
conditions prevail. Color cannot be relied upon as
indicating the need for an oil change. The use of an oil
4-56. ENGINE LUBRICATION SYSTEM.
analysis service is the only reason for not following the
change interval specified in Table 4-1. When checking
the oil level, make sure that the area around the dipstick
and filler cap are clean before removing them.
4-58. Engine lubrication oil should be kept up to the FULL
mark on the dipstick. To accurately check the oil level,
stop the engine and allow approximately five minutes for
the oil to drain off of engine internal parts.
eliminates the possibility of overfilling. The oil should
generally be changed every 100 hours or two weeks, or
The Detroit Diesel oil filter should be changed each time
more often where adverse
the oil is changed. Clean the outside of the filter flange to
prevent dirt from entering the engine. Be sure that a new
HYSTER-APPROVED filter and gasket are installed.