MCi Crusader II 1989 Maintenance Manual page 201

Date
1-1-89,
Page·_. __
6 -_ 2 _ _
MC-9 MAINTENANCE MANUAL
must operate in proper sequence to prevent coolant temper-
ature instability and/ or engine overheating. An improper
operating sequence can also have a detrimental effect on the
life of the "add on" components as well. ·
The following chart gives the nominal temperature settings
tor the 180° F (82° C) thermostat and shutterstat controls. along
with standard and optional alarmstat settings. These settings
should not be exceeded. under any engine operating condition.
regardless of operating altitude. type of coolant used. or cooling
system condition Exceeding the settings will unnecessarily
increase the engine coolant and lubricating oil temperature.
NOTE: Coolant temperature instability will
result from improper component operating
sequence.
ENGINE COOLANT OUT TEMPERAT\JRE
EHGailt 'THEJIIMOSTAT EJtGINf TltEJIMOSTAT ALUtll SE'TTWG A1.A1tM SETT'NQ
BEQafta~O~ ALLY,OPEN tST~AIIOJ ( ~
T•W•
T
l'l
:::.._,, 7 1
!(i<sL?p\LC(s( (s(s
<,,q
arc: u•c
02"'= We:
1°'•e
l
SMITTDSTAT
IECIMSTO ~
SHIIITDtS
Figure 6-2. Nominal Settings For Coolant
• Temperature Controls.
The maIor components of tt1e cooling sys.tern are the coo-
1ant. radiators. blower gear box and surge tank. The~e com-
ponents. as well as the minor ones. are covered in more detail
iater In this section.
HOSE INSPECTION
Swollen. cracked or worn out hoses or loose hose connec-
tions are frequent causes of cooling system problems.
Serious overheating Is often caused by old hose collapsing
or from deteriorated rubber shedding from hoses and clogging
the coolant passages.
Connections should be inspected periodically and hose
clamps tightened. Replace any hose found to be cracked or
swollen. When installing a new hose. clean pipe connections
and apply a thin layer of a non-hardening sealing compound.
Replace worn out clamps or clamps that pinch hoses.
TESTING ANTIFREEZE SOLUTIONS
Always test solution before adding water or antifreeze.
Engine should be warmed to operating temperature. Fill and
empty tester several times before using. and ensure that tester
Is clean inside and out.
If a coolant filter Is us.ed. replace the ele~ent every 500 hours
or 20.000 miles (32.000 km).
Commercial cooling system cleaners of alkaline or acid type
may be used. Exercise extreme caution and follow the manu-
facturer's recommendations when using these types of
cleaners.
Problems may develop from leaks and seepage at the
engine water pump and thermostat housings hose connec-
tions. These may be caused by deformation and rough surfaces
on the castings at the hose mounting surfaces. It is recom-
mended that Dow Corning RTV-102 Compound be applied to
cast surfaces prior to hose installation.
CAUTION: Castings should be clean and
free of oil and grease before applying com-
pound. No other sealer should be used with
RTV compound.
COLD WEATHER OPERATIONS
Although not recommended. plain water with an inhibitor
may be used as a coolant where temperatures do not reacr1
below 32°F (0°C). In colder regions antifreeze must be used.
Before adding antifreeze the cooling system should be
inspected for winter operation. Cylinder head gaskets should
be tightened or replaced where necessary to avoid the possibil-
ity of coolant leaking into engine and exhaust gases blowing
into cooling system.
After antifreeze has been added. the entire system should be
inspected regularly to ensure against the devefopment of leaks.
If the cooling system becomes frozen. place the coach in a
warm area until the ice is completely thawed. Under no circum-
stances should the engine be operated when the cooling sys-
tem Is frozen.
PREVE~TIVE MAINTENANCE
A program of maintenance of the cooling system com-
ponents Is essential to ensure maximum system efficiency. and
trouble-free operation. Observe the following guidelines:
1. Check. on a daily basis. the coolant level in the·surge tank.
Keep tank filled with the coolant required for proper operation
In the extremes of seasonal temperatures.
2. Every 20.000 miles (32.000 km) perform the following
checks:
a. Check belts for condition and tension. Tighten loose
belts and replace those frayed or worn.
b. Check water pump operation and installation. A leaking
pump will suck air into the i:;ooling system. causing corrosion of
engine and cooling system components. and decreasing the
efficiency of the coolant. Correct all leaks at once.
c. Check the radiators and all hoses for leaks. Repair leak-
ing components. Clean the radiator cores with low pressure air
to remove all dirt and :hus provide optimum heat dissipation.
Check and ti-;ihten radiator mounts as required. Repair all leaks.
d. If a coolant filter is used. replace the element at this
interval.
3. The following procedures are necessary every 100.000
miles 1161.000 km):
a. Check the strength of the antifreeze with a hydrometer.
If too weak. drain a quantity of coolant from the system. and
replace with the same quantity of coolant (water
I
antifreeze
mixture) In proper proportion to result in correct overall solution
strength.
· b. Check the strength of the inhibitor in the coolant. Use a
test kit or strip made available by the manufacturer of the inhibi-
tor In use. Follow the instructions of the inhibitor manufacturer.
Add 1nhib1tor only in the amount necessary to reach manufac-
turer·s strength recommendations.