STEYR MOTORS Marine Engine 2012 Series, Service Manual

Page: 208 / 274

Cooling System
Z001138-1_2013-02-01 2/21
Items to Check / Troubled Systems
Raw Water & Fresh Water Coolant System
[Factors/Cause of Trouble]
E
ngine ov
er
heat
ing
E
ngine c
ooling li
quid t
em
p.
Rem
ains
low
los
s
of
c
ooling liquid
Low (
dr
op in)
engine out
put
A
bnor
m
al nois
e
Lar
ge blow
-by
gas
em
is
s
ion
c
ooling liqu
id T
em
p.
(
inlet
/
out
let
) B
alanc
e is
lar
ge
c
ooling liqu
id inlet
/out
let
t
em
p.
B
ala
nc
e is
s
m
all
Dam
age of
Raw W
a
ter
P
um
p
Im
peller
B
ubbles
in t
he Radiat
or
/
Heat
E
x
c
hanger
Coolant
dis
c
har
ged f
rom
E
x
pans
ion T
ank
A
CT
Lim
it
ex
c
eeded (
>
65°
)
E
CT
G
auge I
ndic
at
ion t
o s
how
120°
C
Dis
c
olor
at
ion of
c
ooling liqui
d
Raw W
at
er
pum
p
Poly V-belt slip or breakage
• • •
Water leaks due to defective seal packing
• •
Air is picked in bevor Raw Water Pump • • •
Breakage of bearing at Raw Water Pump
• • • • •
Obstructed Raw Water Supply (Closed Sea
Cock)
• • •
Breakage of impeller
• • • • •
c
oolant
syst
e
m
Water leakage from cooling system
• •
Scale accumulated in cooling system
• • • •
Inferior thermostat performance
• • • •
Heat
E
x
c
hanger
Core fin clogged or collapsed • •
Defective radiator cap
• • •
Water leakage
• •
Clogged by scale or other substances
• • • •
O
ther
s
Continuous overload operation
• • •
Faulty indication of ECT gauge
• • •
Clogging or collapse of exhaust pipe or muffler
• • •
Faulty copper insert
• •
Leakage of Oil Cooler into Coolant
• • •
Gas leakage from cylinder block
• • • • • •