PS Magazine - TB 43-PS-692
PS, The Preventative Maintenance Monthly
ISSUE 692
JULY 2010
12
PS 692
JUL 10
D
oes your unit have HMMWVs with serial number 300,000 or higher? If so, your
HMMWV could have a faulty combination oil cooler.
The combination oil cooler contains engine oil, transmission oil and power steering
fluids. Problems with the power steering oil cooler segments have been reported to
TACOM LCMC. The power steering fluid flow tubes are located within the center
section of the combination oil cooler.
These
tubes
could
expand
or rupture during initial engine
warm-up or start-up, especially
when the vehicle’s hydraulic
system
is
cold.
A
ruptured
power steering cooler causes a
loss of power steering fluid and
pressure, making your HMMWV
hard to steer. Braking will also
suffer because the power hydro-
boost is also affected. You don’t
need hard steering or braking,
especially in a war zone!
2.
Perform a one-minute engine warm-up in normal operations and a three-minute
engine warm-up in cold weather operations (32°F and below). And make sure you
don’t use your steering and braking systems during warm-up! Then, re-inspect the
combination oil cooler for leaks.
If you ±nd a faulty oil cooler, your HMMWV is
NMC!
And it’ll stay that way
until the combination oil cooler is replaced. By the way, an oil cooler relief valve
retro±t kit has been developed to prevent premature failure of the combination oil
cooler. But your HMMWV isn’t NMC if this retro±t kit is not installed.
The oil cooler and relief valve kit is a one-time free issue for units with HMMWVs
that have serial number 300,000 or higher.
And TACOM SOUM 10-007 tells you all about this problem. View it online if
you haven’t yet:
Inspect Like the TM Says!
Avoid this by inspecting the combination oil cooler for ruptures, leaks or swollen
tubes like the PMCS table in TM 9-2320-387-10 says. Here’s a quick reminder, as
it relates to the oil cooler:
1.
Both before and after driving your HMMWV, visually check underneath the truck
for fluid leaks. If leakage is detected, ±nd the location and cause of the leak. See if
that oil cooler is the culprit.
Use the Warranty
HMMWV…
Oil
C
ler
Failure
Dead-
lines
Truck!
Failure example: Ruptured power steering flow tube
why are you
going off the
road?
I can’t help it!
I’m having a hard
time turning the
steering wheel
and braking this
hmmwv!
well, maybe you
should have inspected
the combination oil
cooler for
damages
before we left!
that could have
affected
the
steering and
braking!
Complete the warranty
forms found on these
links to receive the
combination oil cooler
retrofit kit and the
combination oil cooler…
Then email the completed
paperwork to:
milserv@amgeneral.com
692.12-13.indd
1-2
5/24/10
5:09:08 PM
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