Jeep Wrangler/YJ 1987-1995 Repair Guide

Engine

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REMOVAL & INSTALLATION



2.5L Engine
  1. Disconnect the battery ground cable.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Remove the hood.
  6.  
  7. Drain the coolant.
  8.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the lower radiator hose.
  2.  
  3. Remove the upper radiator hose.
  4.  
  5. Disconnect the coolant recovery hose.
  6.  
  7. Remove the fan shroud.
  8.  
  9. Disconnect the automatic transmission coolant lines.
  10.  
  11. Discharge the refrigerant system. See General Information & Maintenance .
  12.  


CAUTION
Do this CAREFULLY, or let someone with experience and the proper equipment do it for you. Great personal injury can occur when mishandling refrigerant gas!

  1. Disconnect and remove the condenser. Cap all openings at once!
  2.  
  3. Remove the radiator.
  4.  
  5. Remove the fan and install a 5 / 16 in. x 1 / 2 in. capscrew through the pulley and into the water pump flange to maintain the pulley-to-pump alignment.
  6.  
  7. Disconnect the heater hoses.
  8.  
  9. Disconnect the throttle linkage.
  10.  
  11. Disconnect the cruise control linkage.
  12.  
  13. Disconnect the oil pressure sending unit wire.
  14.  
  15. Disconnect the temperature sending unit wire.
  16.  
  17. Disconnect and tag all vacuum hoses connected to the engine.
  18.  
  19. Remove the air conditioning compressor.
  20.  
  21. Remove the power steering hoses at the gear.
  22.  
  23. Drain the power steering reservoir.
  24.  
  25. Remove the power brake vacuum check valve from the booster.
  26.  
  27. Raise and support the front end on jackstands.
  28.  
  29. Disconnect and tag the starter wires.
  30.  
  31. Remove the starter.
  32.  
  33. Disconnect the exhaust pipe at the manifold.
  34.  
  35. Remove the flywheel housing access cover.
  36.  
  37. On vehicles equipped with automatic transmission, matchmark the converter and flywheel and remove the attaching bolts.
  38.  
  39. Remove the upper flywheel housing-to-engine bolts and loosen the lower ones.
  40.  
  41. Remove the engine mount cushion-to-engine compartment bolts.
  42.  
  43. Attach a shop crane to the lifting eyes on the engine.
  44.  
  45. Raise the engine off the front supports.
  46.  
  47. Place a floor jack under the flywheel housing.
  48.  
  49. Remove the remaining flywheel housing bolts.
  50.  
  51. Lift the engine out of the vehicle.
  52.  
  53. Mount the engine on a work stand or cradle. Never let it rest on the oil pan.
  54.  

To install:
  1. Lower the engine into place in the vehicle.
  2.  
  3. Lubricate the manual transmission input shaft with chassis lube before insertion into clutch splines.
  4.  
  5. Install the flywheel housing bolts. Torque the top flywheel housing-to-engine bolts to 27 ft. lbs. (37 Nm) and the bottom ones to 43 ft. lbs. (58 Nm).
  6.  
  7. Install the engine mount cushion-to-engine compartment bolts. Torque the front bracket support bolts to 33 ft. lbs. (45 Nm).
  8.  
  9. Remove the shop crane.
  10.  
  11. On vehicles equipped with automatic transmission, install the converter attaching bolts.
  12.  
  13. Install the flywheel housing access cover.
  14.  
  15. Connect the exhaust pipe at the manifold.
  16.  
  17. Install the starter.
  18.  
  19. Connect the wires.
  20.  
  21. Raise and support the front end on jackstands.
  22.  
  23. Install the power brake vacuum check valve on the booster.
  24.  
  25. Fill the power steering reservoir.
  26.  
  27. Connect the power steering hoses at the gear.
  28.  
  29. Install the air conditioning compressor.
  30.  
  31. Connect all vacuum hoses.
  32.  
  33. Connect all wires.
  34.  
  35. Connect the throttle linkage.
  36.  
  37. Connect the cruise control linkage.
  38.  
  39. Connect the heater hoses.
  40.  
  41. Install the fan.
  42.  
  43. Install the radiator.
  44.  
  45. Install the condenser.
  46.  
  47. Evacuate and charge the refrigerant system. See General Information & Maintenance .
  48.  


CAUTION
Do this CAREFULLY, or let someone with experience do it for you. Great personal injury can occur when mishandling refrigerant gas!

  1. Install the fan shroud.
  2.  
  3. Connect the automatic transmission coolant lines.
  4.  
  5. Install the upper radiator hose.
  6.  
  7. Connect the coolant recovery hose.
  8.  
  9. Install the lower radiator hose.
  10.  
  11. Fill the cooling system.
  12.  
  13. Install the hood.
  14.  
  15. Install the air cleaner.
  16.  
  17. Connect the battery ground cable.
  18.  

4.0L Engine
  1. Place a protective cloth on the windshield frame. Raise the hood and rest it on the frame.
  2.  
  3. Disconnect the battery cables and remove the battery.
  4.  
  5. Properly relieve the fuel system pressure.
  6.  

Label all electrical connectors and vacuum lines prior to disconnecting them, so they can be reinstalled in their proper locations.

  1. Drain the cooling system.
  2.  
  3. Disconnect the wires from the alternator.
  4.  
  5. Disconnect the ignition coil and distributor wire connections.
  6.  
  7. Disconnect the oil pressure sending unit connector.
  8.  
  9. Disconnect the wires from the starter.
  10.  
  11. Disconnect the fuel injection wires.
  12.  
  13. Disconnect the fuel lines from the fuel rails.
  14.  
  15. Remove the fuel line bracket from the intake manifold.
  16.  
  17. Disconnect the engine ground strap.
  18.  
  19. Remove the air cleaner assembly.
  20.  
  21. Disconnect the canister purge hose from the vapor canister "T'' connector.
  22.  
  23. Disconnect the idle speed actuator wire connector.
  24.  
  25. Disconnect the throttle cable and remove it from the bracket.
  26.  
  27. Disconnect the throttle rod from the bellcrank.
  28.  
  29. If equipped, disconnect the cruise control cable.
  30.  
  31. Detach the oxygen sensor electrical connector.
  32.  
  33. Disconnect the upper and lower hoses from the radiator.
  34.  
  35. Disconnect the coolant hoses from the rear of the intake manifold and thermostat housing.
  36.  
  37. Disconnect the heater hoses.
  38.  
  39. Remove the fan shroud screws.
  40.  
  41. Remove the radiator and fan shroud.
  42.  
  43. Remove the engine cooling fan.
  44.  
  45. Remove the engine cooling fan and install a 5 / 16 x 1 / 2 inch capscrew through the fan pulley into the water pump flange. This will maintain the pulley and water pump in alignment when the crankshaft is rotated.
  46.  
  47. If equipped, disconnect the check valve from the power brake booster.
  48.  
  49. If equipped with power steering, perform the following:
    1. Disconnect the steering hoses from the fittings at the steering gear.
    2.  
    3. Drain the pump reservoir.
    4.  
    5. Cap all fittings once removed.
    6.  

  50.  
  51. Raise and support the vehicle safely.
  52.  
  53. Remove the oil filter.
  54.  
  55. Remove the starter.
  56.  
  57. Remove the flywheel access cover.
  58.  
  59. Remove the engine support cushion-to-bracket through bolts.
  60.  
  61. Disconnect the exhaust pipe from the manifold.
  62.  
  63. Remove the upper flywheel housing bolts and loosen the bottom bolts.
  64.  
  65. Remove the engine shock damper bracket from the sill.
  66.  
  67. Lower the vehicle.
  68.  
  69. Attach a lifting device to the engine.
  70.  
  71. Place a support under the bellhousing.
  72.  
  73. Remove the remaining flywheel bolts.
  74.  
  75. Lift the engine from the vehicle.
  76.  
  77. Install the oil filter to keep foreign material out of the engine.
  78.  

To install:
  1. Remove the oil filter.
  2.  
  3. Lower the engine into the vehicle. To ease installation, remove the engine support cushions to aid in engine-to-transmission alignment.
  4.  
  5. Insert the transmission shaft into the clutch spline.
  6.  
  7. Align the flywheel housing with the engine.
  8.  
  9. Install and tighten the flywheel housing bolts finger-tight.
  10.  
  11. If removed, install the engine support cushions.
  12.  
  13. Lower the engine into place and remove the lifting device.
  14.  
  15. Raise and support the vehicle safely.
  16.  
  17. Attach the engine shock damper bracket to the sill.
  18.  
  19. Attach the exhaust pipe to the manifold and torque the nuts to 23 ft. lbs. (31 Nm).
  20.  
  21. Install the flywheel access cover.
  22.  
  23. Install the remaining flywheel bolts and torque them to 28 ft. lbs. (38 Nm).
  24.  
  25. Install the starter.
  26.  
  27. Install the oil filter.
  28.  
  29. Lower the vehicle.
  30.  
  31. Connect the coolant lines and tighten the clamps.
  32.  
  33. If equipped with power steering.
    1. Connect the hoses to the steering gear and torque the nut to 38 ft. lbs. (52 Nm).
    2.  
    3. Fill the pump reservoir with fluid.
    4.  

  34.  
  35. Remove the alignment capscrew and install the fan assembly.
  36.  
  37. Install the accessory drive belt.
  38.  
  39. Install the radiator and shroud.
  40.  
  41. Connect the radiator hoses.
  42.  
  43. Attach the oxygen sensor electrical connector.
  44.  
  45. Connect the throttle valve rod and retainer. Connect the throttle cable and install the rod and spring.
  46.  
  47. If equipped, connect the speed control cable.
  48.  
  49. Install the vacuum hose and check valve to the brake booster.
  50.  
  51. Connect the electrical connections disconnected during removal.
  52.  
  53. Connect the fuel lines to the fuel rail.
  54.  
  55. Install the fuel line bracket to the intake manifold.
  56.  
  57. Install the air cleaner.
  58.  
  59. Install the battery and connect the cables.
  60.  
  61. Fill the engine to the proper level with oil.
  62.  
  63. Fill the cooling system.
  64.  
  65. Start the engine and check for leaks.
  66.  
  67. Fill the fluid levels to the proper level.
  68.  

4.2L Engine
  1. Remove the air cleaner.
  2.  
  3. Drain the cooling system.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the upper and lower radiator hoses.
  2.  
  3. If equipped with an automatic transmission, disconnect the cooler lines from the radiator.
  4.  
  5. Remove the radiator and the fan. If the Jeep has air conditioning, evacuate the system, remove the condenser and cap all openings immediately. See General Information & Maintenance .
  6.  
  7. If so equipped, remove the power steering pump and the drive belt, and place the unit aside. Do not remove the power steering hoses.
  8.  
  9. If the vehicle has air conditioning, remove the compressor.
  10.  
  11. Disconnect all wires, lines, linkage, and hoses that are connected to the engine. Remove the oil filter.
  12.  
  13. Remove both of the engine front support cushion-to-frame retaining nuts.
  14.  
  15. Disconnect the exhaust pipe at the support bracket and exhaust manifold.
  16.  
  17. Support the weight of the engine with a lifting device.
  18.  
  19. Remove the front support cushion and bracket assemblies from the engine.
  20.  
  21. Remove the transfer case shift lever boot and the transmission access cover.
  22.  
  23. If equipped with an automatic transmission, remove the upper bolts securing the transmission bellhousing to the engine. If equipped with a manual transmission, remove the upper bolts that secure the clutch housing to the engine.
  24.  
  25. Remove the starter motor.
  26.  
  27. If the vehicle is equipped with an automatic transmission:
    1. Remove the engine to transmission adapter plate inspection covers.
    2.  
    3. Mark the assembled position of the converter and flex plate and remove the converter-to-flex plate retaining screws.
    4.  
    5. Remove the remaining bolts securing the transmission bellhousing to the engine.
    6.  

  28.  
  29. If equipped with a manual transmission, remove the lower cover of the clutch housing and the remaining bolts that secure the clutch housing to the engine.
  30.  
  31. Support the transmission with a floor jack.
  32.  
  33. Attach a suitable sling to the engine and using a hoist, lift the engine upward and forward at the same time, removing it from the vehicle.
  34.  

To install:
  1. Lower the engine into the vehicle and slide it rearward to engage the transmission.
  2.  
  3. If equipped with an automatic transmission, install the upper bolts securing the transmission bellhousing to the engine. Torque them to 27 ft. lbs. (37 Nm). If equipped with a manual transmission, install the upper bolts that secure the clutch housing to the engine. Torque them to 27 ft. lbs. (37 Nm).
  4.  
  5. If equipped with a manual transmission, install the lower cover of the clutch housing and the remaining bolts that secure the clutch housing to the engine. Torque the clutch housing spacer-to-bolts to 12-15 ft. lbs. (16-20 Nm). Torque the clutch housing lower bolts to 43 ft. lbs. (58 Nm).
  6.  
  7. If the vehicle is equipped with an automatic transmission:
    1. Install the remaining bolts securing the transmission bellhousing to the engine. Torque the bellhousing lower bolts to 43 ft. lbs. (58 Nm).
    2.  
    3. Mark the assembled position of the converter and flex plate and install the converter-to-flex plate retaining screws. Torque the bolts to 20-25 ft. lbs. (27-34 Nm).
    4.  
    5. Install the engine to transmission adapter plate inspection covers.
    6.  

  8.  
  9. Install the starter motor. Torque the mounting bolts to 18 ft. lbs. (25 Nm).
  10.  
  11. Install the transfer case shift lever boot and the transmission access cover.
  12.  
  13. Install the front support cushion and bracket assemblies from the engine.
  14.  
  15. Remove the shop crane.
  16.  
  17. Connect the exhaust pipe at the support bracket and exhaust manifold. Torque the nuts to 20 ft. lbs. (27 Nm).
  18.  
  19. Install both of the engine front support cushion-to-frame retaining nuts. Torque them to 35 ft. lbs. (47 Nm).
  20.  
  21. Connect all wires, lines, linkage, and hoses that are connected to the engine.
  22.  
  23. Install the oil filter.
  24.  
  25. If so equipped, install the power steering pump and the drive belt.
  26.  

If the vehicle has air conditioning, mount and connect the air conditioning compressor. See Chassis Electrical .

  1. Install the radiator and the fan, and the condenser.
  2.  
  3. Evacuate, charge and leak test the refrigerant system.
  4.  
  5. If equipped with an automatic transmission, connect the cooler lines to the radiator.
  6.  
  7. Connect the upper and lower radiator hoses.
  8.  
  9. Fill the cooling system.
  10.  
  11. Install the air cleaner.
  12.  

 
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