LUBE OIL COOLER AND FILTER BYPASS VALVE
The lube oil cooler is mounted on the right side of the
engine cylinder block and receives coolant from the
Engine lubricating oil is pumped
through a chamber in the lube oil cooler. The cham-
ber walls are cooled by the coolant and, in turn,
maintain the engine lube oil at a safe operating tem-
14-33. Removal, Disassembly, and Cleaning of Oil
a. Removal. Refer to the Operator and Organiza-
tional Maintenance Manual for removal procedures.
See figure 14-17 and disassem-
ble the lube oil cooler as shown.
Clean all metallic park with clean-
ing-solvent, Federal Specification P-D-680.
14-34. Inspection and Repair.
(1) Inspect cooler housing, bonnet, and header
for cracks, distortion, and scoring of mating sur-
(2) Inspect cooler assembly passages for ob-
(1) Clean passages with steam under
to insure that there are no obstructions.
(2) Smooth burrs or scoring on mating surfaces
with a fine mill file.
(3) Replace any parts damaged beyond repair.
(4) Discard all gaskets and preformed packing.
14-35. Test, Reassembly, and Installation.
(1) Make up two plates, one with a drilled and
tapped hole to accept an air hose fitting, and secure
them with C clamps to cover the oil inlet and outlet
openings in the side of the oil cooler.
Use the pre-
formed packing to seal the plates.
(2) Attach an air hose to the drilled and tapped
plate; submerge the oil cooler in hot water until the
oil cooler temperature is up to approximately
Test for leaks with air pressure of 100 psi.
(3) No air bubbles shall appear at either
end of the lube oil cooler.
If the cooling core
faulty, the oil cooler must be replaced. If the shell
is damaged it must be replaced.
(1) See figure 14-17 and reassemble the lube
(2) After reassembly, place the lube oil cooler
on a surface plate as if it were being mounted. Us-
ing a feeler gauge, check to see if all machined sur-
faces contact the plate within 0. 005 inch. Loosen
and retighten screws to obtain this clearance.
c. Installation. Refer to the Operator and Organ-
izational Maintenance Manual.
14-36. Lube Oil Filter Bypass Valve.
The lube oil filter bypass valve is part of the header
block of the engine lube oil filter assembly. If the
filters become clogged, such that the differential
pressure across the combination of both filters
rises to 45 psi the bypass valve opens permitting
unfiltered oil to bypass the filters and go directly
to the main oil gallery.
Cold weather induced thickening of the oil will cause
the filters to be bypassed. As the engine oil warms
the by-pass valve will close inserting the filter ele-
ments into the oil stream.
(See figure 14-18)
(1) Both oil filters must be removed. Refer to
Operator and Organization Maintenance Manual.
(2) Remove the oil filter header block by re-
moving six cap screws.
(3) Thoroughly clean the area at the rear of the
header block where the bypass valve is located.
(4) Remove the cap, gasket, spring, piston
sleeve and seat.
c. Cleaning and Inspection.
Wash valve parts in cleaning solvent. Inspect care-
fully for wear or damage. Replace any worn or
(1) Install valve
(2) Renew filter
bypass valve gasket.
in reverse order of disassem-
header gaskets and lube oil