Page 5217 of 5267
5. The NVLD pump snaps into the EVAP canister.
Press on release tab (2) while rotating pump from
canister.
INSTALLATION
If Equipped With Horizontally Mounted EVAP Canisters
Page 5218 of 5267
The NVLD pump (4) is attached to the EVAP canister.
1. Install new O-ring to EVAP canister.
Page 5219 of 5267
2. Align NVLD assembly into EVAP canister.
3. Rotate NVLD assembly until alignment tab drops
into slot.
4. Connect electrical connector to NVLD assembly.
5. Carefully install vapor/vacuum lines to NVLD pump.
The vapor/vacuum lines and hoses must be
firmly connected. Check the vapor/vacuum
lines at the NVLD pump, filter and EVAP canis-
ter purge solenoid for damage or leaks. If a leak
is present, a Diagnostic Trouble Code (DTC)
may be set.
6. If necessary, install skid plate(s).
Page 5220 of 5267
If Equipped With Vertically Mounted EVAP Canisters
The NVLD pump (4) is located at the front of fuel tank.
1. Snap NVLD pump (1) to EVAP canister until tab (2)
engages.
2. Connect electrical connector to NVLD pump.
3. Carefully install vapor/vacuum lines to NVLD pump.
The vapor/vacuum lines and hoses must be
firmly connected. Check the vapor/vacuum
lines at the NVLD pump, filter and EVAP canis-
ter purge solenoid for damage or leaks. If a leak
is present, a Diagnostic Trouble Code (DTC)
may be set.
4. If equipped, install skid plate(s).
Page 5221 of 5267
VA LV E - P C V
DESCRIPTION
3.7L V-6 / 4.7L V-8
The 3.7L V-6 and 4.7L V-8 engines are equipped with
a closed crankcase ventilation system and a Positive
Crankcase Ventilation (PCV) valve (6).
This system consists of:
a PCV valve mounted to the oil filler housing.
The PCV valve is sealed to the oil filler housing
with an o-ring.
the air cleaner housing
two interconnected breathers (1) threaded into
the rear of each cylinder head.
tubes and hoses to connect the system
components.
Page 5222 of 5267
5.7L V-8
The 5.7L V-8 engine is equipped with a closed crank-
case ventilation system and a Positive Crankcase
Ventilation (PCV) valve (4).
This system consists of:
a PCV valve mounted into the top of the intake
manifold, located to the right / rear of the throttle
body. The PCV valve (1) is sealed to the intake
manifold with 2 o-rings (2).
passages in the intake manifold.
tubes and hoses to connect the system
components.
Page 5223 of 5267

OPERATION
A typical enclosed crankcase ventilation system is
shown in the graphic.
The PCV system operates by engine intake manifold
vacuum. Filtered air is routed into the crankcase
through the air cleaner hose. The metered air, along
with crankcase vapors, are drawn through the PCV
valve (4) and into a passage in the intake manifold.
The PCV system manages crankcase pressure and
meters blow by gases to the intake system, reducing
engine sludge formation.
The PCV valve contains a spring loaded plunger. This
plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.
When the engine is not operating or during an engine
pop-back, the spring forces the plunger back against
the seat. This will prevent vapors from flowing through
the valve.
During periods of high manifold vacuum, such as idle
or cruising speeds, vacuum is sufficient to completely
compress spring. It will then pull the plunger to the top
of the valve. In this position there is minimal vapor
flow through the valve.
Page 5224 of 5267

During periods of moderate manifold vacuum, the
plunger is only pulled part way back from inlet. This
results in maximum vapor flow through the valve.
DIAGNOSIS AND TESTING
PCVVALVE-3.7LV-6/4.7LV-8
1. Disconnect PCV line/hose (5) by disconnecting rub-
ber connecting hose at PCV valve fitting.
2. Remove PCV valve at oil filler tube by rotating PCV
valve downward until locating tabs (2) have been
freed at cam lock (3). After tabs have cleared, pull
valve straight out from filler tube.To prevent dam-
age to PCV valve locating tabs, valve must be
pointed downward for removal. Do not force
valve from oil filler tube.
3. After valve is removed, check condition of valve
O-ring (1). Also, PCV valve should rattle when
shaken.
4. Reconnect PCV valve to its connecting line/hose.
5. Start engine and bring to idle speed.
6. If valve is not plugged, a hissing noise will be
heard as air passes through valve. Also, a strong
vacuum should be felt with a finger placed at valve
inlet.
7. If vacuum is not felt at valve inlet, check line/hose
for kinks or for obstruction. If necessary, clean out
intake manifold fitting at rear of manifold. Do this
byturninga1/4inchdrill(byhand)throughthefittingtodislodgeanysolid particles. Blow out the fitting with
shop air. If necessary, use a smaller drill to avoid removing any metal fromthe fitting.
8.Do not attempt to clean the old PCV valve.
9. Return PCV valve back to oil filler tube by placing valve locating tabs (2) into cam lock (3). Press PCV valve in
and rotate valve upward. A slight click will be felt when tabs have engaged cam lock. Valve should be pointed
towards rear of vehicle.
10. Connect PCV line/hose (5) and connecting rubber hose to PCV valve.
11. Disconnect rubber hose from fresh air fitting at air cleaner resonatorbox. Start engine and bring to idle speed.
Hold a piece of stiff paper (such as a parts tag) loosely over the opening of the disconnected rubber hose.