Jeep Grand Cherokee WK. Manual - part 215
DIAGNOSIS AND TESTING - RADIATOR PRESSURE CAP
Remove cap from radiator. Be sure that sealing sur-
faces are clean. Moisten rubber gasket with water and
install the cap on pressure tester (tool 7700 or an
equivalent).
Operate the tester pump and observe the gauge
pointer at its highest point. The cap release pressure
should be 110 to 138 kPa (16 - 20 psi). The cap is
satisfactory when the pressure holds steady. It is also
good if it holds pressure within the 110 - 138 kPa (16
- 20 psi) range for 30 seconds or more. If the pointer
drops quickly, replace the cap.
CAUTION: Radiator pressure testing tools are very
sensitive to small air leaks, which will not cause
cooling system problems. A pressure cap that
does not have a history of coolant loss should not
be replaced just because it leaks slowly when
tested with this tool. Add water to tool. Turn tool
upside down and recheck pressure cap to confirm
that cap needs replacement.
CLEANING
Clean the radiator pressure cap using a mild soap and water only.
INSPECTION
Visually inspect the pressure valve gasket on the cap. Replace cap if the gasket is swollen, torn or worn. Inspect
the area around radiator filler neck for white deposits that indicate a leaking cap.
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ENGINE
WK