Radiator Description; Radiator Pressure Cap Description And Operation; Cross Flow Radiator; Radiator Pressure Cap And Filler Neck— Typical - Jeep 200 Cherokee Service Manual

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DESCRIPTION AND OPERATION (Continued)
RADIATOR
DESCRIPTION
CAUTION: Plastic tanks, while stronger than brass,
are subject to damage
wrenches.
Radiators for both engines are the cross flow type.
Plastic tanks are used on all radiators.
Fig. 8 Cross Flow Radiator
1 – RADIATOR
RADIATOR PRESSURE CAP
DESCRIPTION
All radiators are equipped with a pressure cap.
This cap releases pressure at some point within a
range of 83-110 kPa (12-16 psi). The pressure relief
point (in pounds) is engraved on top of the cap (Fig.
9).
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap contains a spring-
loaded pressure relief valve that opens when system
pressure reaches release range of 83-110 kPa (12-16
psi).
by impact, such as
A rubber gasket seals radiator filler neck. This is
done to maintain vacuum during coolant cool-down
and to prevent leakage when system is under pres-
sure.
Fig. 9 Radiator Pressure Cap and Filler Neck—
1 – FILLER NECK SEAL
2 – VACUUM VENT VALVE
3 – PRESSURE RATING
4 – PRESSURE VALVE
OPERATION
A vent valve in the center of cap allows a small
coolant flow through cap when coolant is below boil-
ing temperature. The valve is completely closed when
boiling point is reached. As the coolant cools, it con-
tracts and creates a vacuum in the cooling system.
This causes the vacuum valve to open and coolant in
the reserve/overflow tank to be drawn through its
connecting hose into radiator. If the vacuum valve is
stuck shut, the radiator hoses will collapse on cool-
down.
COOLING SYSTEM
Typical
7 - 5