2001 DODGE RAM lock

PISTON & CONNECTING ROD
DESCRIPTION
The pistons are made of aluminum and have three
ring grooves, the top two grooves are for the compres-
sion rings and the bottom groove is for the oil control
ring. The connecting rods are forged steel and are
coined prior to heat treat. The piston pins are press
fit.
STANDARD PROCEDUREÐPISTON FITTING
Check the cylinder block bore for out-of-round,
taper, scoring, or scuffing.
Check the pistons for taper and elliptical shape
before they are fitted into the cylinder bore (Fig. 39).
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin-
der wall is 0.013-0.038 mm (0.0005-0.0015 in.) at
21ÉC (70ÉF).
Piston diameter should be measured at the top of
skirt, 90É to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans-
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
PISTON MEASUREMENTS CHART
PISTON A DIA = PISTON BORE
SIZE DIAMETER DIAMETER
MIN. MAX. MIN. MAX.
mm
(in.)mm
(in.)mm
(in.)mm (in.)
A99.280 99.294 99.308 99.320
(3.9087) (3.9092) (3.9098) (3.9103)
B99.294 99.306 99.320 99.333
(3.9092) (3.9097) (3.9103) (3.9108)
C99.306 99.319 99.333 99.345
(3.9097) (3.9102) (3.9108) (3.9113)
D99.319 99.332 99.346 99.358
(3.9102) (3.9107) (3.9113) (3.9118)
E99.332 99.344 99.358 99.371
(3.9107) (3.9112) (3.9118) (3.9123)
DESCRIPTION SPECIFICATION
PISTON PIN BORE 25.007 - 25.014 mm
(.9845 - .9848 in.)
RING GROOVE
HEIGHT4.0309 - 4.0538 mm
(OIL RAIL) (.1587 - .1596 in.)
RING GROOVE
HEIGHT2.0294 - 2.0548 mm
(COMPRESSION
RAIL)(.0799 - .0809 in.)
TOTAL FINISHED 594.6   2 grams
WEIGHT (20.974   .0706 ounces)
REMOVAL
(1) Remove the engine from the vehicle (Refer to 9
- ENGINE - REMOVAL).
(2) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(3) Remove the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(4) Remove top ridge of cylinder bores with a reli-
able ridge reamer before removing pistons from cyl-
inder block. Be sure to keep tops of pistons covered
during this operation.
(5) Be sure each connecting rod and connecting rod
cap is identified with the cylinder number. Remove
connecting rod cap. Install connecting rod bolt guide
set on connecting rod bolts.
(6) Pistons and connecting rods must be removed
from top of cylinder block. When removing the
assemblies from the engine, rotate crankshaft so that
Fig. 39 Piston Measurements
1 - 62.230 mm
(2.45 IN.)
9 - 40 ENGINE 3.9LBR/BE

the connecting rod is centered in cylinder bore and at
BDC.Be careful not to nick crankshaft journals.
(7) After removal, install bearing cap on the mat-
ing rod.
CLEANING
Clean the piston and connecting rod assembly
using a suitable solvent.
INSPECTION
Check the connecting rod journal for excessive
wear, taper and scoring (Refer to 9 - ENGINE/EN-
GINE BLOCK/CONNECTING ROD BEARINGS -
STANDARD PROCEDURE).
Check the connecting rod for signs of twist or bend-
ing.
Check the piston for taper and elliptical shape
before it is fitted into the cylinder bore (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON & CONNECT-
ING ROD - STANDARD PROCEDURE).
Check the piston for scoring, or scraping marks in
the piston skirts. Check the ring lands for cracks
and/or deterioration.
INSTALLATION
(1) Be sure that compression ring gaps are stag-
gered so that neither is in line with oil ring rail gap.
(2) Before installing the ring compressor, be sure
the oil ring expander ends are butted and the rail
gaps located properly (Fig. 40).(3) Immerse the piston head and rings in clean
engine oil. Slide Piston Ring Compressor Tool C-385
over the piston and tighten with the special wrench
(part of Tool C-385).Be sure position of rings
does not change during this operation.
(4) Install connecting rod bolt protectors on rod
bolts. The long protector should be installed on the
numbered side of the connecting rod.
(5) Rotate crankshaft so that the connecting rod
journal is on the center of the cylinder bore. Be sure
connecting rod and cylinder bore number are the
same. Insert rod and piston into cylinder bore and
guide rod over the crankshaft journal.
(6) Tap the piston down in cylinder bore, using a
hammer handle. At the same time, guide connecting
rod into position on crankshaft journal.
(7) The notch, or groove, on top of piston must be
pointing toward front of engine. The larger chamfer
of the connecting rod bore must be installed toward
crankshaft journal fillet.
(8) Install rod caps. Be sure connecting rod, con-
necting rod cap, and cylinder bore number are the
same. Install nuts on cleaned and oiled rod bolts and
tighten nuts to 61 N´m (45 ft. lbs.) torque.
(9) Install the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(10) Install the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - INSTALLATION).
(11) Install the engine into the vehicle (Refer to 9 -
ENGINE - INSTALLATION).
PISTON RINGS
STANDARD PROCEDUREÐPISTON RING
FITTING
(1) Measurement of end gaps:
(a) Measure piston ring gap 2 in. from bottom of
cylinder bore. An inverted piston can be used to
push the rings down to ensure positioning rings
squarely in the cylinder bore before measuring.
(b) Insert feeler gauge in the gap. The top com-
pression ring gap should be between 0.254-0.508
mm (0.010-0.020 in.). The second compression ring
gap should be between 0.508-0.762 mm
(0.020-0.030 in.). The oil ring gap should be 0.254-
1.270 mm (0.010-0.050 in.).
(c) Rings with insufficient end gap may be prop-
erly filed to the correct dimension. Rings with
excess gaps should not be used.
(2) Install rings, and confirm ring side clearance:
(a) Install oil rings being careful not to nick or
scratch the piston. Install the oil control rings
according to instructions in the package. It is not
necessary to use a tool to install the upper and
Fig. 40 Proper Ring Installation
1 - OIL RING SPACER GAP
2 - SECOND COMPRESSION RING GAP OIL RING RAIL GAP
(TOP)
3 - OIL RING RAIL GAP (BOTTOM)
4 - TOP COMPRESSION RING GAP
BR/BEENGINE 3.9L 9 - 41
PISTON & CONNECTING ROD (Continued)

lower rails. Insert oil rail spacer first, then side
rails.
(b) Install the second compression rings using
Installation Tool C-4184. The compression rings
must be installed with the identification mark face
up (toward top of piston) and chamfer facing down.
An identification mark on the ring is a drill point,
a stamped letter ªOº, an oval depression, or the
word ªTOPº (Fig. 41) (Fig. 43).
(c) Using a ring installer, install the top com-
pression ring with the chamfer facing up (Fig. 42)
(Fig. 43). An identification mark on the ring is a
drill point, a stamped letter ªOº, an oval depression
or the word ªTOPº facing up.
(d) Measure side clearance between piston ring
and ring land. Clearance should be 0.074-0.097 mm
(0.0029-0.0038 in.) for the compression rings. The
steel rail oil ring should be free in groove, but
should not exceed 0.246 mm (0.0097 in.) side clear-
ance.
(e) Pistons with insufficient, or excessive, side
clearance should be replaced.
(3) Orient the rings:
(a) Arrange top compression ring 90É counter-
clockwise from the oil ring rail gap (Fig. 44).
(b) Arrange second compression ring 90É clock-
wise from the oil ring rail gap (Fig. 44).
VIBRATION DAMPER
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove fan, and fan drive (Refer to 7 - COOL-
ING/ENGINE/FAN DRIVE VISCOUS CLUTCH -
REMOVAL).(3) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove the vibration damper pulley.
(5) Remove vibration damper bolt and washer from
end of crankshaft.
(6) Install bar and screw from Puller Tool Set
C-3688. Install two bolts with washers through the
puller tool and into the vibration damper (Fig. 45).
(7) Pull vibration damper off of the crankshaft.
INSTALLATION
(1) Position the vibration damper onto the crank-
shaft.
(2) Place installing tool, part of Puller Tool Set
C-3688, in position and press the vibration damper
onto the crankshaft (Fig. 46).
Fig. 41 Second Compression Ring Identification
(Typical)
1 - SECOND COMPRESSION RING (BLACK CAST IRON)
2 - CHAMFER
3 - TWO DOTS
Fig. 42 Top Compression Ring Identification
(Typical)
1 - TOP COMPRESSION RING (GRAY IN COLOR)
2 - CHAMFER
3 - ONE DOT
Fig. 43 Compression Ring Chamfer Location
(Typical)
1 - CHAMFER
2 - TOP COMPRESSION RING
3 - SECOND COMPRESSION RING
4 - PISTON
5 - CHAMFER
9 - 42 ENGINE 3.9LBR/BE
PISTON RINGS (Continued)

(3) Install the crankshaft bolt and washer. Tighten
the bolt to 244 N´m (180 ft. lbs.) torque.
(4) Install the crankshaft pulley. Tighten the pul-
ley bolts to 23 N´m (200 in. lbs.) torque.(5) Install the serpentine belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(6) Install viscous fan drive and fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - INSTALLATION).
(7) Install the fan shroud.
(8) Connect the negative cable to the battery.
FRONT MOUNT
REMOVAL
(1) Disconnect the battery negative cable.
(2) Position fan to ensure clearance for radiator
top tank and hose.
CAUTION: DO NOT lift the engine by the intake
manifold.
(3) Install engine support/lifting fixture.
(4) Raise vehicle on hoist.
(5) Lift the engine SLIGHTLY and remove the
thru-bolt and nut (Fig. 47).
(6) Remove engine support bracket/cushion bolts
(Fig. 47). Remove the support bracket/cushion and
heat shields.
INSTALLATION
(1) With engine raised SLIGHTLY, position the
engine support bracket/cushion and heat shields to
the block. Install new bolts and tighten to 81 N´m (60
ft. lbs.) torque.
(2) Install the through-bolt into the engine support
bracket/cushion.
Fig. 44 Proper Ring Installation
1 - OIL RING SPACER GAP
2 - SECOND COMPRESSION RING GAP OIL RING RAIL GAP
(TOP)
3 - OIL RING RAIL GAP (BOTTOM)
4 - TOP COMPRESSION RING GAP
Fig. 45 Vibration Damper Assembly
1 - SPECIAL TOOL C-3688
Fig. 46 Installing Vibration Damper
1 - SPECIAL TOOL C-3688
Fig. 47 Engine Front Mounts
1 - ENGINE MOUNT HEAT SHIELD
2 - THRU-BOLT
3 - RESTRICTION PADS
4 - ENGINE SUPPORT BRACKET/CUSHION
BR/BEENGINE 3.9L 9 - 43
VIBRATION DAMPER (Continued)

(3) Using the transmission jack, lower the trans-
mission and support cushion onto the crossmember
(Fig. 49).
(4) Install the support cushion bolts and tighten to
41 N´m (30 ft. lbs.) torque.
(5) Remove the transmission jack.
(6) Lower the vehicle.
LUBRICATION
DESCRIPTION
A gear-type positive displacement pump (Fig. 50)is
mounted at the underside of the rear main bearing
cap. The pump uses a pick-up tube and screen
assembly to gather engine oil from the oil pan.
OPERATION
The pump draws oil through the screen and inlet
tube from the sump at the rear of the oil pan. The oil
is driven between the drive and idler gears and
pump body, then forced through the outlet to the
block. An oil gallery in the block channels the oil to
the inlet side of the full flow oil filter. After passing
through the filter element, the oil passes from the
center outlet of the filter through an oil gallery that
channels the oil up to the main gallery, which
extends the entire length on the right side of the
block. The oil then goes down to the No. 1 main bear-
ing, back up to the left side of the block, and into the
oil gallery on the left side of the engine.
Galleries extend downward from the main oil gal-
lery to the upper shell of each main bearing. The
crankshaft is drilled internally to pass oil from the
main bearing journals to the connecting rod journals.
Each connecting rod bearing has half a hole in it, oil
passes through the hole when the rods rotate and the
hole lines up, oil is then thrown off as the rod
rotates. This oil throwoff lubricates the camshaft
lobes, distributor drive gear, cylinder walls, and pis-
ton pins.The hydraulic valve tappets receive oil directly
from the main oil gallery. The camshaft bearings
receive oil from the main bearing galleries. The front
camshaft bearing journal passes oil through the cam-
shaft sprocket to the timing chain. Oil drains back to
the oil pan under the No. 1 main bearing cap.
The oil supply for the rocker arms and bridged
pivot assemblies is provided by the hydraulic valve
tappets, which pass oil through hollow push rods to a
hole in the corresponding rocker arm. Oil from the
rocker arm lubricates the valve train components.
The oil then passes down through the push rod guide
holes and the oil drain-back passages in the cylinder
head, past the valve tappet area, and then returns to
the oil pan (Fig. 51).
Fig. 50 Positive Displacement Oil PumpÐTypical
1 - INNER ROTOR AND SHAFT
2 - BODY
3 - DISTRIBUTOR DRIVESHAFT (REFERENCE)
4 - COTTER PIN
5 - RETAINER CAP
6 - SPRING
7 - RELIEF VALVE
8 - LARGE CHAMFERED EDGE
9 - BOLT
10 - COVER
11 - OUTER ROTOR
BR/BEENGINE 3.9L 9 - 45
REAR MOUNT (Continued)

(6) Add oil only if level is below the ADD mark on
dipstick.
ENGINE OIL CHANGE:
Change engine oil at mileage and time intervals
described in the Maintenance Schedule. This infor-
mation can be found in the owner's manual.
TO CHANGE ENGINE OIL
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Hoist vehicle.
(3) Remove oil fill cap.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug and
gasket if damaged.
(6) Install drain plug in crankcase.
(7) Change oil filter (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL).
(8) Lower vehicle and fill crankcase with specified
type (Refer to LUBRICATION & MAINTENANCE/
FLUID TYPES - DESCRIPTION) and amount of
engine oil (Refer to LUBRICATION & MAINTE-
NANCE - SPECIFICATIONS).
(9) Install oil fill cap.
(10) Start engine and inspect for leaks.
(11) Stop engine and inspect oil level.
OIL FILTER
REMOVAL
All engines are equipped with a high quality full-
flow, disposable type oil filter. DaimlerChrysler Cor-
poration recommends a Mopartor equivalent oil
filter be used.
(1) Position a drain pan under the oil filter.
(2) Using a suitable oil filter wrench loosen filter.
(3) Rotate the oil filter counterclockwise to remove
it from the cylinder block oil filter boss (Fig. 53).
(4) When filter separates from adapter nipple, tip
gasket end upward to minimize oil spill. Remove fil-
ter from vehicle.
(5) With a wiping cloth, clean the gasket sealing
surface (Fig. 54) of oil and grime.
(6) Install new filter (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - INSTALLATION).
INSTALLATION
(1) Lightly lubricate oil filter gasket with engine
oil or chassis grease.
(2) Thread filter onto adapter nipple. When gasket
makes contact with sealing surface, (Fig. 54) hand
tighten filter one full turn, do not over tighten.
(3) Add oil (Refer to 9 - ENGINE/LUBRICATION/
OIL - STANDARD PROCEDURE).
OIL PAN
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove engine oil dipstick.
(3) Raise vehicle.
(4) Drain engine oil.
(5) Remove exhaust pipe.
(6) Remove left engine to transmission strut.
(7) Loosen the right side engine support bracket
cushion through-bolt nut and raise the engine
slightly. Remove oil pan by sliding backward and out.
(8) Remove the one-piece gasket.
Fig. 53 Oil Filter RemovalÐTypical
1 - ENGINE OIL FILTER
2 - OIL FILTER WRENCH
Fig. 54 Oil Filter Sealing SurfaceÐTypical
1 - SEALING SURFACE
2 - RUBBER GASKET
3 - OIL FILTER
9 - 48 ENGINE 3.9LBR/BE
OIL (Continued)

CLEANING
Clean the block and pan gasket surfaces.
Trim or remove excess sealant film in the rear
main cap oil pan gasket groove.DO NOT remove
the sealant inside the rear main cap slots.
If present, trim excess sealant from inside the
engine.
Clean oil pan in solvent and wipe dry with a clean
cloth.
Clean oil screen and pipe thoroughly in clean sol-
vent. Inspect condition of screen.
INSPECTION
Inspect oil drain plug and plug hole for stripped or
damaged threads. Repair as necessary.
Inspect oil pan mounting flange for bends or distor-
tion. Straighten flange, if necessary.
INSTALLATION
(1) Clean the block and pan gasket surfaces.
(2) Fabricate four alignment dowels from 5/16 X 1
1/2 inch bolts. Cut the head off the bolts and cut a
slot into the top of the dowel. This will allow easier
installation and removal with a screwdriver (Fig. 55).
(3)
Install the dowels in the cylinder block (Fig. 56).
(4) Apply small amount of MopartSilicone Rubber
Adhesive Sealant, or equivalent, in the corner of the
cap and the cylinder block.
(5) Slide the one-piece gasket over the dowels and
onto the block.
(6) Position the oil pan over the dowels and onto
the gasket.
(7) Install the oil pan bolts. Tighten the bolts to 24
N´m (215 in. lbs.) torque.
(8)
Remove the dowels. Install the remaining oil pan
bolts. Tighten these bolts to 24 N´m (215 in. lbs.) torque.
(9) Lower the engine into the support cushion
brackets and tighten the through-bolt nut to the
proper torque.(10) Install the drain plug. Tighten drain plug to
34 N´m (27 ft. lbs.) torque.
(11) Install the engine to transmission strut.
(12) Install exhaust pipe.
(13) Lower vehicle.
(14) Install dipstick.
(15) Connect the negative cable to the battery.
(16) Fill crankcase with oil to proper level.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 2±wire, electrical/mechanical engine oil pres-
sure sensor (sending unit) is located in an engine oil
pressure gallery.
OPERATION
The oil pressure sensor uses two circuits. They are:
²
A signal to the PCM relating to engine oil pressure
²A sensor ground through the PCM's sensor return
The oil pressure sensor returns a voltage signal
back to the PCM relating to engine oil pressure. This
signal is then transferred (bussed) to the instrument
panel on a CCD bus circuit to operate the oil pres-
sure gauge and the check gauges lamp. Ground for
the sensor is provided by the PCM through a low-
noise sensor return.
Fig. 55 Fabrication of Alignment Dowels
1 - 5/16º X 1óº BOLT
2 - DOWEL
3 - SLOT
Fig. 56 Position of Dowels in Cylinder Block
1 - DOWEL
2 - DOWEL
3 - DOWEL
4 - DOWEL
BR/BEENGINE 3.9L 9 - 49
OIL PAN (Continued)

DIAGNOSIS AND TESTINGÐINTAKE
MANIFOLD LEAKAGE
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS, OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPMs, the area of the suspected
leak has been found.
(4) Repair as required.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Remove the A/C compressor (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
COMPRESSOR - REMOVAL).
(4) Remove the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - REMOVAL).
(5) Remove the accessory drive bracket.
(6) Remove the air cleaner.
(7) Perform the Fuel System Pressure release pro-
cedure (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY - STANDARD PROCEDURE). Disconnect the
fuel lines (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(8) Disconnect the accelerator linkage (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/THROTTLE
CONTROL CABLE - REMOVAL) and if so equipped,
the speed control and transmission kickdown cables.
(9) Remove the return spring.
(10) Remove the distributor cap and wires.
(11) Disconnect the coil wires.
(12) Disconnect the heat indicator sending unit
wire.
(13) Disconnect the heater hoses and bypass hose.
(14) Remove the closed crankcase ventilation and
evaporation control systems.
(15) Remove intake manifold bolts.
(16) Lift the intake manifold and throttle body out
of the engine compartment as an assembly.
(17) Remove and discard the flange side gaskets
and the front and rear cross-over gaskets.(18) Remove the throttle body (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/THROTTLE BODY -
REMOVAL).
(19) If required, remove the plenum pan and gas-
ket. Discard gasket.
CLEANING
Clean manifold in solvent and blow dry with com-
pressed air.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
The plenum pan rail must be clean and dry (free of
all foreign material).
INSPECTION
Inspect manifold for cracks.
Inspect mating surfaces of manifold for flatness
with a straightedge.
INSTALLATION
(1) If the plenum pan was removed, position a new
gasket and install the plenum pan (Fig. 67). Tighten
bolts in the following sequence:
²Step 1. Tighten bolts to 5.4 N´m (48 in. lbs.)
²Step 2. Tighten bolts to 9.5 N´m (84 in. lbs.)
²Step 3. Check bolts to 9.5 N´m (84 in. lbs.)
(2) Install the flange gaskets. Ensure that the ver-
tical port alignment tab is resting on the deck face of
the block. Also the horizontal alignment tabs must be
in position with the mating cylinder head gasket tabs
(Fig. 69). The words MANIFOLD SIDE should be vis-
ible on the center of each flange gasket.
Fig. 67 Plenum Pan Bolt Tightening Sequence
BR/BEENGINE 3.9L 9 - 53
INTAKE MANIFOLD (Continued)