Table of Contents
Advertisement
7- 4
COOLING SYSTEM
DESCRIPTION AND OPERATION (Continued)
COOLANT RESERVE/OVERFLOW SYSTEM
The system works along with the radiator pressure
cap . This is done by using thermal expansion and
contraction of the coolant to keep the coolant free of
trapped air. It provides :
" A volume for coolant expansion and contraction .
" A convenient and safe method for checking/ad-
justing coolant level at atmospheric pressure . This is
done without removing the radiator pressure cap.
" Some reserve coolant to the radiator to cover
minor leaks and evaporation or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine . Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
The coolant reserve/overflow system consists of a
radiator mounted pressurized cap, a plastic coolant
recovery bottle (Fig. 4), a tube (hose) connecting the
radiator and recovery bottle, and an overflow tube on
the side of the bottle .
RADIATOR
PRESSURE CAP
Fig. 4 Coolant Recovery Bottle
BLOCK NEATER SPECIFICATIONS
" 2 .5L 4-Cylinder Engine : 115 Volts 400 Watts
" 4 .OL 6-Cylinder Engine: 120 Volts 600 Watts
HOSE
80a5572a
BLOCK HEATER
The heater unit is mounted in a block core hole
and is immersed in coolant. The heater uses ordinary
house current (110 Volt A .C.) and should never be
pluged in unless it is immersed in coolant .
WARNING:
DO NOT OPERATE 'ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
TJ
THERMOSTAT
A pellet-type thermostat controls the operating
temperature of the engine by controlling the amount
of coolant flow to the radiator. On all engines the
thermostat is closed below 195°F (90°C) . Above this
temperature, coolant is allowed to flow to the radia-
tor. This provides quick engine warm-up and overall
temperature control .
An arrow plus the word UP is stamped on the
front flange next to the air bleed. The words TO
RAD are stamped on one arm of the thermostat.
They indicate the proper installed position.
The same thermostat is used for winter and sum-
mer seasons. An engine should not be operated with-
out a thermostat, except for servicing or testing .
Operating without a thermostat causes other prob-
lems. These are: longer engine warm-up time, unre-
liable
warm-up
performance,
increased
exhaust
emissions and crankcase condensation. This conden-
sation can result in sludge formation.
CAUTION:
Do not operate an engine without a
thermostat, except for servicing or testing .
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water
mixture depends upon climate and vehicle operating
conditions . The coolant performance of various mix-
tures follows :
Pure Water-Water can absorb more heat than a
mixture of water and ethylene-glycol . This is for pur-
pose of heat transfer only. Water also freezes at a
higher temperature and allows corrosion .
100
percent
Ethylene-Glycol-The
corrosion
inhibiting additives in ethylene-glycol need the pres-
ence of water to dissolve . Without water, additives
form deposits in system . These act as insulation
causing temperature to rise to as high as 149°C
(300°F) . This temperature is hot enough to melt plas-
tic and soften solder. The increased temperature can
result in engine detonation . In addition, 100 percent
ethylene-glycol freezes at -22°C (-8°F) .
50/50 Ethylene-Glycol and Water-Is the recom-
mended mixture, it provides protection against freez-
ing to -37°C (-34°F) . The antifreeze concentration
must always be a minimum of 44 percent, year-
round in all climates. If percentage is lower, engine
parts may be eroded by cavitation. Maximum protec-
tion against freezing is provided with a 68 percent
antifreeze concentration,
which prevents freezing
down to -67 .7°C (-90°F) . A higher percentage will
freeze at a warmer temperature . Also, a higher per-
centage of antifreeze can cause the engine to over-
heat because specific heat of antifreeze is lower than
that of water.
Advertisement
Table of Contents
Troubleshooting
