Genuine 1994 Jeep Wrangler Cylinder Head

1994 Jeep Wrangler Cylinder Head Parts Questions & Experts Answers

• Q: How to remove and replace a cylinder head in 4.0L and 4.2L V6 engine on 1994 Jeep Wrangler?

  A: Disconnect the negative cable from the battery and drain the cooling system. Remove the air cleaner assembly, detach the fuel pipe and vacuum advance hose, and take off the valve cover. Remove the rocker arms and pushrods, then unbolt the power steering pump bracket (if equipped) and set the pump aside without disconnecting the hoses, keeping it upright to prevent fluid spillage. Remove the intake and exhaust manifolds, and take off the bracket on the cylinder head that supports the idler pulley for the air conditioning compressor drivebelt. Loosen the alternator drivebelt and remove the alternator bracket-to-cylinder head mounting bolt. Unplug the wiring and unbolt the air conditioning compressor without disconnecting the refrigerant hoses, setting the compressor aside while removing the upper two bolts from the bracket. Label the spark plug wires and remove the distributor cap with the wires attached, then take out the spark plugs. Disconnect the wire from the temperature sending unit located on the top left rear corner of the cylinder head, and also disconnect the battery ground cable on the right side of the engine. Remove the ignition coil and bracket assembly, and if equipped, remove the heater hose bracket by disconnecting the two bolts. Remove the cylinder head bolts and lift the head off the engine, noting that bolt number 14 cannot be removed until the cylinder head is moved forward to clear the firewall. If the head sticks, gently pry it loose using a prybar in an exhaust port. Clean the gasket mating surfaces thoroughly, ensuring all old gasket material is removed, and stuff shop towels into each cylinder to prevent debris from falling in. Inspect the head for cracks and warpage, and if replacing the cylinder head, transfer all fittings to the new head. For models equipped with the 4.2L engine, apply an even coat of Perfect Seal sealing compound to both sides of the replacement head gasket, while for the 4.0L engine, no sealant is necessary. Position the new head gasket on the engine block with the word TOP facing up, then install the cylinder head. Coat the threads of bolt number 11 with Loctite 592 sealant and install the head bolts hand-tight, ensuring each bolt is clean and marked with a dab of paint, replacing any reused bolts. Tighten the cylinder head bolts in sequence to the specified torque values, then reinstall the remaining components in reverse order of removal. Finally, add coolant and run the engine, checking for proper operation and any coolant or oil leaks.