Doosan DX60R Shop Manual page 250

Check and Adjust Cooling Fan V-Belt
The V-belt will slip if it does not have the proper tension. This will
prevent the alternator from generating sufficient power. Also, the
engine will overheat due to the engine coolant pump pulley slipping.
Check and adjust the V-belt tension (deflection) as follows:
1. Press the V-belt down with your thumb with a force of
approximately 22 ft•lb (98 N•m; 10 kgf) to check the
deflection.
There are three positions to check for V-belt tension (A, B
and C, Figure 78). You can check the tension at whichever
position is the most accessible. The proper deflection of a
used V-belt at each position is:
A
3/8 - 1/2 in.
(10 - 14 mm)
NOTE: A "Used V-Belt" refers to a V-belt which has been
used on a running engine for five minutes or more.
2. If necessary, adjust the V-belt tension. Loosen the
adjusting bolt (1, Figure 79) and move the alternator (2,
Figure 79) with a pry bar (3, Figure 79) to tighten the V-belt
to the desired tension. Then tighten the adjusting bolt.
3. Tighten the V-belt to the proper tension. There must be
clearance (1, Figure 80) between the V-belt and the
bottom of the pulley groove. If there is no clearance (2,
Figure 80) between the V-belt and the bottom of the pulley
groove, replace the V-belt.
4. Check the V-belt for cracks, oil or wear. If any of these
conditions exist, replace the V-belt.
5. Install the new V-belt. Refer to the table for proper tension.
A
5/16 - 7/16 in.
(8 - 12 mm)
6. After adjusting, run the engine for 5 minutes or more. Check
the tension again using the specifications for a used V-belt.
A
3/8 - 1/2 in.
(10 - 14 mm)
Engine
Page 70
Used V-Belt Tension
B
1/4 - 3/8 in.
(7 - 10 mm)
Used V-Belt Tension
B
3/16 - 5/16 in.
(5 - 8 mm)
Used V-Belt Tension
B
1/4 - 3/8 in.
(7 - 10 mm)
C
5/16 - 1/2 in.
(9 - 13 mm)
Figure 78
Figure 79
1
C
1/4 - 7/16 in. Figure 80
(7 - 11 mm)
C
5/16 - 1/2 in.
(9 - 13 mm)
2
FG008859
SP001693