OPERATION
The front check valve provides more than one func-
tion in this application. It prevents washer fluid from
draining out of the front washer supply hoses back to
the washer reservoir. This drain-back would result in
a lengthy delay from when the front washer switch is
actuated until washer fluid was dispensed through
the front washer nozzle, because the front washer
pump would have to refill the front washer plumbing
from the reservoir to the nozzle. Such a drain-back
condition could also result in water, dirt, or other
outside contaminants being siphoned into the washer
system through the washer nozzle orifice. This water
could subsequently freeze and plug the nozzle, while
other contaminants could interfere with proper noz-
zle operation and cause improper nozzle spray pat-
terns. In addition, the front check valve prevents
washer fluid from siphoning out through the front
washer nozzle after the front washer system is
turned Off.
When the front washer pump pressurizes and
pumps washer fluid from the reservoir through the
front washer plumbing, the fluid pressure unseats a
diaphragm from over a sump well within the valve
by overriding the spring pressure applied to it by a
piston (Fig. 4). With the diaphragm unseated, washer
fluid is allowed to flow toward the front washer noz-
zle. When the front washer pump stops operating,
the spring pressure on the piston seats the dia-
phragm over the sump well in the valve and fluid
flow in either direction within the front washer
plumbing is prevented. The front check valve cannot
be adjusted or repaired and, if faulty or damaged, it
must be replaced.
REMOVAL
(1) Unlatch, open and support the hood.
(2) Locate the front check valve in the washer sup-
ply hose for the front washer nozzle. The check valve
is installed in the washer supply hose about 5 centi-
meters (2 inches) from the front washer nozzle nipple
near the rear hood panel reinforcement (Fig. 5).
(3) Disconnect the washer supply hose for the
front washer nozzle from the barbed outlet nipple on
the front washer system check valve. A small quan-
tity of washer fluid may drain from the disconnected
hose.
(4) Disconnect the washer supply hose for the res-
ervoir from the barbed inlet nipple of the front check
valve. Either install a temporary plug in the washer
supply hose for the reservoir or secure the loose end
of this hose at a point higher than the washer reser-
voir to prevent the contents of the washer reservoir
from draining through this hose.
(5) Remove the front check valve from the engine
compartment.
Fig. 4 Front Check Valve
1 - SPRING
2 - PISTON
3 - DIAPHRAGM
4 - TO WASHER NOZZLE
5 - FROM WASHER PUMP
Fig. 5 Front Check Valve Remove/Install
1 - HOOD REAR REINFORCEMENT
2 - FRONT WASHER NOZZLE
3 - WASHER HOSE
4 - FRONT CHECK VALVE
TJ
FRONT WIPERS/WASHERS
8R - 9
FRONT CHECK VALVE (Continued)