3.9L V6 Engine & 5.2L V8 Engine & 5.9L V8 Engine: Other Dodge Durango I

SPECIAL ENGINE MARKS

Information identifying undersize and oversize components is found at various engine locations and is decoded as follows

Crankshaft & Rod Journals

1. The letter "M" (main) or "R" (rod) followed by number indicates which main or rod bearing journal is .001" (.02 mm) undersize. The mark is stamped on No. 6 crankshaft counterweight on 3.9L engine, No. 8 crankshaft counterweight on 5.2L engine and No. 3 crankshaft counterweight on 5.9L engine.

Cylinder Block

1. Letter "A" following engine serial number indicates .020" (.51 mm) oversize cylinder bores
2. A diamond-shaped stamp, located on top pad at front of engine and stamped on flat area of each oversize lifter bore, indicates .008" (.20 mm) oversize lifters.
3. A stamp "X" indicates .005" (.13 mm) oversize valve stems. The stamp is found on machined pad, near two 3/8" tapped holes on each end of cylinder head.

FUEL PRESSURE RELEASE

Fuel Pressure Release - Gasoline

1. Disconnect negative battery cable. Loosen fuel tank cap to release tank pressure. Press on filler tube flap to relieve any additional tank pressure. NOTE: Fuel filler tube has spring-loaded flap located below fuel fill cap to serve as secondary seal if fuel fill cap is not tightened. It is part of EVAP monitor system when vehicle is equipped with Leak Detection Pump (LDP). Vehicle may be equipped with flap installed into fuel filler tube even if vehicle is not equipped with LDP and EVAP monitor system.
2. Remove fuel pump relay from Power Distribution Center (PDC). For location of relay, refer to label on underside of PDC cover. Start and run engine until it stalls. Attempt restarting engine until it will no longer run.
3. Unplug connector from an injector. Attach one end of a jumper wire (18 gauge or smaller) with alligator clips to either injector terminal. Connect other end of jumper wire to positive side of battery. Connect one end of a second jumper wire to remaining injector terminal. WARNING: Powering an injector for more than a few seconds will permanently damage injector.
4. Touch other end of second jumper wire to negative terminal of battery for no more than a few seconds. Place a rag below fuel line. Disconnect quick-connect fitting at fuel rail. See «FUEL LINE DISCONNECT FITTINGS»(ref-97388-S13486016262001050300000) . Install fuel pump relay into PDC.

Compressed Natural Gas Fuel Tube Purging (5.2L)

1. Close control valve (clockwise) on all fuel cylinders. Open manual shutoff valve (open when handle is parallel to fuel tubes).
2. Start and operate engine until it runs out of fuel. Attempt 3 more engine starts. If check valve or fuel fill receptacle is to be serviced, slowly loosen inlet side of fuel fill tube fitting at check valve. It is normal for approximately 25 psi of residual natural gas pressure to flow from loosened fitting. At this point, all fuel tubes are purged of natural gas between fuel cylinders and engine. It is now okay to open fuel system. WARNING: Fuel cylinders still contain high-pressure fuel.

Compressed Natural Gas Fuel Cylinder Purging (5.2L)

1. Open manual shutoff valve. Open only fuel control valve(s) (counterclockwise) on fuel cylinder(s) to be serviced. Close all other control valve(s) (clockwise) on fuel cylinder(s) not being serviced.
2. Start and operate engine until it runs out of fuel. Attempt 3 more engine starts. At this point, all fuel tubes and opened cylinders are purged of natural gas between fuel cylinders and engine. It is now okay to open fuel system. WARNING: Fuel cylinders not being serviced still contain high-pressure fuel.

Cylinder Head

Check cylinder head warpage. Repair or replace cylinder head if warpage exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS.

Valve Springs

1. Check valve spring free length, out-of-square and pressure. Replace valve spring if not within specification. See «VALVES & VALVE SPRINGS»(ref-97388-S16996842642001050300000) table under ENGINE SPECIFICATIONS.
2. Measure valve spring installed height from bottom of spring seat (cylinder head surface) to bottom of spring retainer. If spacers are installed, measure from top of spacer.
3. If height exceeds 1.687" (42.86 mm), install a .066" (1.58 mm) thick spacer in cylinder head counterbore to obtain correct installed spring height. See «VALVES & VALVE SPRINGS»(ref-97388-S16996842642001050300000) table under ENGINE SPECIFICATIONS.

Valve Stem Oil Seals

Cup-type oil seals are used on all valves. Ensure oversize valve stem oil seals are used when oversize valves are installed. When installing valves, DO NOT over compress valve springs, or damage to valve stem oil seal may result.

Valve Guides

Note. DO NOT ream valve guides from standard to maximum oversize in one step. Ream valve guides to oversize in gradual steps so guides are reamed true in relation to valve seat. After reaming valve guides, valve seat runout must be checked.

Check valve stem oil clearance. Ensure valve stem diameter is within specification. Valve guide must be reamed for valve with oversize valve stem if oil clearance exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. Valves are available with stems of .015" (.38 mm) and .030" (.76 mm) oversize.

Valve Seat

Check valve seat width and runout. Grind valve seat if not within specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS.

Valves

Ensure valve margin, head diameter and stem diameter are within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Valves are available with stems of .015" (.38 mm) and .030" (.76 mm) oversize.

Valve Seat Correction Angles

Use a 15-degree stone to lower valve seat, and a 60-degree stone to raise valve seat.

Rocker Arms & Pivots

Remove rocker arms and pivots. Inspect for wear. Replace as necessary.

Valve Lifters

Note. Cylinder block must be marked to indicate oversize valve lifters. See SPECIAL ENGINE MARKS .

Measure valve lifter diameter and bore diameter in cylinder block. Determine oil clearance. Clearance must be within specification. See VALVE LIFTERS table under ENGINE SPECIFICATIONS. Cylinder block can be bored for oversize lifters.

Fitting Pistons

1. Measure piston diameter at top of piston skirt at 90-degree angle to piston pin axis. Measure cylinder bore diameter below top surface of cylinder bore, middle of bore and bottom of cylinder bore.
2. Ensure piston diameter and clearance are within specification. See «PISTONS, PINS & RINGS»(ref-97388-S12788998092001050300000) table under ENGINE SPECIFICATIONS.

Piston Rings

1. Ensure ring end gap and side clearances are within specification. See «PISTONS, PINS & RINGS»(ref-97388-S12788998092001050300000) table under ENGINE SPECIFICATIONS.
2. Position piston ring gaps in proper location. (Scheme 17) Compression ring gaps must be staggered so they do not align with oil ring rail gap. Ensure identification marks (drill point, letter "O", an oval depression or the word TOP) on compression rings face upward.

Scheme 17

Rod Bearings

1. Crankshaft is marked to indicate undersize rod bearings. See «SPECIAL ENGINE MARKS»(ref-97388-S38068377642001050300000) . When replacing connecting rod bearings, ensure connecting rod is installed with larger chamfer of connecting rod bore toward crankshaft journal fillet.
2. Apply light coat of engine oil to connecting rod bolt threads before tightening nut to specification. See «TORQUE SPECIFICATIONS»(ref-97388-S37732293522001050300000) . Ensure oil clearance and side play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-97388-S29016325182001050300000) table under ENGINE SPECIFICATIONS.

Crankshaft & Main Bearings

1. Crankshaft is marked to indicate undersize main bearings. See «SPECIAL ENGINE MARKS»(ref-97388-S38068377642001050300000) . Main bearing cap location and direction of installation should be marked before removal.
2. Ensure journal diameter, taper and out-of-round are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-97388-S29016325182001050300000) table under ENGINE SPECIFICATIONS. Upper main bearings contain oil holes, while lower bearings installed in main bearing cap do not.
3. Apply light coat of engine oil to threads before tightening bolt to specification. See «TORQUE SPECIFICATIONS»(ref-97388-S37732293522001050300000) . Ensure oil clearance and end play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-97388-S29016325182001050300000) table under ENGINE SPECIFICATIONS.

Thrust Bearing

Thrust bearing is located on No. 3 main bearing. Replace thrust bearing if crankshaft end play is not within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.

1. Check cylinder bore, out-of-round and taper. Measure cylinder bore diameter below top surface of cylinder bore, middle of bore and bottom of cylinder bore. Bore cylinder block if bore diameter is not within specification. See «CYLINDER BLOCK»(ref-97388-S30283709962001050300000) table under ENGINE SPECIFICATIONS.
2. Check valve lifter bore diameter. Check for scoring. If scoring exists or lifter bore diameter is not within specification, ream cylinder block bore for next oversize valve lifter. See «VALVE LIFTERS»(ref-97388-S15949618252001050300000) table under ENGINE SPECIFICATIONS.

Oil Pressure

Oil pressure is 6 psi (.4 kg/cm 2 ) at idle and 30-80 psi (2.1-5.6 kg/cm 2 ) at 3000 RPM with engine at normal operating temperature.

Scheme 18

OIL LINE PLUG

1. The oil line plug is located in vertical passage in rear of block between oil-to-filter and oil-from-filter passages. (Scheme 19) Missing or improperly installed plug could cause erratic, low or no oil pressure.
2. To check installation, remove oil sending unit and insert wire down passage. Oil line plug should be 7.50-7.68 in. (190.0-195.2 mm) from machined surface of block. If plug is too high, use suitable dowel to position properly. If plug is too low, remove oil pan, oil pump and rear main bearing cap. Use suitable dowel to position properly.
3. To remove for passage cleaning or plug replacement, drive plug from oil sending unit hole out bottom of block. When installing plug, coat outside diameter with Mopar Stud and Bearing Mount Adhesive or equivalent. Plug should be 2.12-2.31 in. (54.0-57.7 mm) from bottom of block.

Scheme 19