TM 5-3810-300-24&P-3
FRESH WATER PUMP 5.1
HIGH CAPACITY FRESH WATER PUMP
Certain six-cylinder engines (effective with engine 6A-
5987), are equipped with a fresh water pump of greater
capacity to provide increased circulation of the coolant.
Six-cylinder turbocharged engines also require the high
capacity pump to compensate for reduced pump speed;
the ratio of blower speed (pump speed) to engine speed
is 1.55:1 for the turbocharged engines and 1.95:1 for
the nonturbocharged engines. However, the standard
pump provides sufficient circulation of the coolant for the
four-cylinder turbocharged engines.
The current pump assembly, effective with engine 6A-
59447, incorporates a new seal assembly and impeller
Fig. 9 - Reworking Diagram of Water Pump Impeller
(Fig. 8). The shaft and bearing assembly and seal
assembly are the same as used in the current standard
between the end of the shaft and the face of the impeller
pump assembly.
hub is .031"-.033", with the bearing being held against
the shoulder in the water pump body.
Service
On former engines which have the end of the shaft
The high capacity pump (Fig. 8) is serviced in the same
tapered press the impeller on the shaft using impeller
manner as the standard pump. However, on current
installer J 9303 until the distance between the end of the
engines, press the impeller on the shaft using impeller
shaft and the face of the impeller hub is .099"-.101" with
installer J 22437 until the distance
the bearing being held against the shoulder in the water
pump body.
Effective with Engine 6A-98234, two 1/4" holes were
added to the water pump impeller (Fig. 9) to vent the
seal chamber and eliminate the possibility of foreign
material build-up between the impeller and the seal,
which could result in a seal leakage. In cases where
pump seal difficulties are encountered, on pumps with
former impellers, it is recommended that the holes be
incorporated.
NOTE:
Remove any rough edges and
burrs from the impeller after drilling the
holes.
The old seal assembly is available for service. However,
if the impeller requires replacement, the current seal
assembly and impeller must be used together. The shaft
with the milled flat must also be replaced if a current
impeller and seal are installed.
Fig. 8 - High Capacity Fresh Water Pumps
NOTE:
The current shaft and bearing
assembly, seal assembly, seal spring, drive
coupling, and pump body insert are the
same for both the standard and high
capacity fresh water pump.
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