Whether you have a Justy, DL or GL, changing the head gasket is a similar process across most Subaru vehicles. A blown gasket can happen for a variety of reasons, ranging from worn or dirty bolts to poorly designed gaskets. Engine overheating is another common culprit. When you replace the head gasket, you practically need to remove and disconnect most of the parts in the engine block.
Assure your Subaru is cold underneath the hood before you start touching parts. Detach the cable off the negative battery. Drain the coolant from the coolant system into a pan or a sealable container. Unscrew the cap in the rear section of the power steering pump or under the air condition compressor. This stops the fluid from flowing into the crankcase and pistons.
Tag and mark the Subaru components in the engine block. Disconnect or remove the ignition wires, air intake ducts, vacuum lines assembly, fuel system pressure and air cleanser outlet tubes. Detach the hoses: heater hose, top radiator hose and coolant bypass hose. Remove the power steering pump belt and the pump for its mount. Sit the parts on a worktable. Leave the hydraulic line intact.
Position padded floor jack with wooden blocks under the Subaru. Disconnect the engine anchor brackets on the left side of the engine situated in the front. Glide the air conditioner compressor belt from the motor and take off the belt tension bracket from the alternator. Remove the distributor anchor and detach the fuel line. Seal the fuel line to stop the fluid from coming out. Loosen the nut of the throttle cable and take it off.
Disconnect or take off the upper motor parts and connections: engine coolant temperature sensor electrical, crankshaft position sensor electrical connector, manifold absolute pressure sensor connection, camshaft position electrical connector and the exhaust gas recirculation valve electrical connector. Note the position of all of the parts and continue to tag and label the parts.
Loosen the cylinder head bolts in the opposite order of installation. Began with the outermost bolt and work towards the center of the cylinder head. Remove and inspect the cylinder head. Install a new cylinder head if it warrants. If you do not replace the cylinder head, clean the mating surface and oil new bolts and the threads before returning to the cylinder block.
Examine the head for the warpage. The warpage should not go above 0.0020 inches. Install the new head gasket and position in the "up" position. Line it up with the dowels. Put the cylinder head on the cylinder block. Install the cylinder head bolts in a three-step process. Torque to 22 foot-pounds for the first step. Torque to 43 foot-pounds for the second step and torque to 47 foot-pounds in the third step.
Return the engine block parts back in the opposite of original factory installation. Review a Subaru service manual for the right bolt torque.
