178 CHA
PTER
EIGHT
Press
ur
e r
eli
ef valve spring
U
pper
sea
lin
g
gasket
Lowe
r seati ng gasket
Upper sealing
surlace
\
~
Sa
fety
sto
p
-::::::::
±::
..--:::
01
Cam l
oc
king su
rlace
:;:::::..---........---
cooling systems and requires the same
type
of
pressure
tester.
1. Remove the pressure fill cap from the heat exchanger.
See Fi
gur
e
Jl
, typical.
2. Wash the cap with clean water to remove any debris or
deposits from its sealing su
rf
aces.
3. Check the gasket.
if so equipped, and rubber seal on
the cap for cuts, cracks. tears
or
deterioration. See Figure
32. Replace the cap if the seal is damaged. Make sure the
locking tabs on the cap are not damaged or bent.
4. Dip the cap in water and attach
it to a cooling system
pres sure lester, using the adapters supplied with the tester.
Sec
F
i
~
u
r
e
33.
5. Pump the pressure to 13 psi (90 kPa).
If
the cap fails to
hold pressure for
)0
seconds without dropping under
11
psi (76 kPa). rep lace it.
6. Inspect the filler neck scat and sealing surface (F
igure
32) for nicks, dents , distortion or contamination. Wipe the
scaling surface with a clean cloth to remove any rust or
dirt. Make sure the locking camsare not bent or damaged .
7. Check coolant level. It should be within I in. (25.4
mm)
ofthc
filler neck. Top ofTif necessary,
8. Connect the cooling system pressure tester to the filler
neck and pressurize the system to 15 psi (104 kPa).
If
pressure does not hold constant for at least
""'·
0minutes,
check all hoses. gaskets, dra in plugs, drain valves and
otherpotential
leak points for leakage. Listen fora hissing
or bubbling sound while the system is under pressure.
9.
If
no leaks are f
ound
. disconnect the seawater outlet
hose from the heat exc hanger (Figure 34). Repressurize
the system 10 IS psi (104 kPa) and note the outlet connec-
tion on the heat exchanger. lf water flows
from the
con
-
nection, air bubbles are visible in the water
or
a bubbling
or hissing noise is heard. there is probably a leak between
the fresh and seawater sections withinthe heal exchanger.
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