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Maintenance Section
Zinc Rods - Inspect/Replace
Visually inspect the water pump for leaks. If any
leaking is observed, replace the water pump
seal or the water pump assembly. Refer to the
Service Manual for the disassembly and assembly
procedure.
Note: Refer to the Service Manual or consult your
Caterpillar dealer if any repair is needed or any
replacement is needed.
i01007424
Zinc Rods - Inspect/Replace
SMCS Code: 1388-040; 1388-510
Corrosion in sea water circuits can result in
premature deterioration of cooling system
components, leaks, and possible cooling system
contamination. The corrosion may be caused by the
lack of zinc rods in the sea water system.
Zinc rods are inserted in the sea water cooling
system of the engine in order to help prevent the
corrosive oxidation that is caused by sea water. The
reaction of the zinc to the sea water causes the
zinc rods to oxidize rather than the cooling system
components. Rapid deterioration of zinc rods may
indicate the presence of uncontrolled electrical
currents from improperly installed electrical
attachments or improperly grounded electrical
attachments.
The zinc rods must be inspected at the proper
intervals. The zinc rods must be replaced when
deterioration occurs.
Inspect the Zinc Rods
The zinc rods are red for easy identification. Table
38 shows the locations of the zinc rods and the
quantities of the zinc rod:
Ta bl e 3 8
Locations of the Zinc Rods
Location Quantity
Heat Exchanger 3
Transmission Oil Cooler
(1)
2
Exhaust Elbow
(2)
1
Aftercooler
(3)
5
(1)
Zinc rods will only be located in marine transmission oil coolers
that are cooled with sea water.
(2)
Exhaust elbows that are aftermarket may or may not be
equipped with zinc rods.
(3)
3126 Engine Only
1. Remove the zinc rod.
2. Inspect the zinc rod.
Ensure that the zinc rod will remain effective until
the next scheduled inspection.
a. If the zinc rod has deteriorated excessively,
install a new zinc rod.
g00481100
Illustration 37
b. Tap the zinc rod lightly with a hammer. If the
zinc rod flakes, install a new zinc rod.
3. If the zinc rod will be reused, scrape the layer of
oxidation from the zinc rod before installation.
The layer of oxidation reduces the effectiveness
of the zinc rod.
Replace the Zinc Rods
1. Unscrew the old zinc rod from the plug.
If not enough material remains or the zinc rod has
broken off, drill the old zinc rod from the plug.
2. Clean the plug.
g00480345
Illustration 38
(1) Shoulder of the zinc rod
(2) Threads of the zinc rod
(3) External threads of the plug
Note: DO NOT apply adhesive or sealant to threads
(2) of the zinc rod.
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