How to Change a Head Gasket
When your car’s exhaust is emitting clouds of steam, you need to learn how to change a head gasket. Changing a head gasket is one of the most time-consuming jobs when working on a car. Below you will find a general list of tools and the steps required to change the head gasket in most cars. It’s highly advisable to purchase the repair manual for your car's make and model so that you have the exact torque sequence and torque values for the head bolts, intake bolts, and exhaust manifold bolts.
Tool List
This is a partial list of tools required for most cars.
- Drain pan for coolant
- Wrench set
- Socket set
- Ratchet
- Socket extensions and universal/swivel
- Screwdrivers
- Gasket scraper
- Shop rags--You’ll want one CLEAN one for each cylinder you expose.
- Spark plug socket
- Pen
- Machine-grade straight edge
Drain the Coolant
Place the pan under the radiator drain and open the valve to allow the coolant to drain. While this is happening, one by one, remove the spark plug wires and label which plug they go to. Loosen the clamps and completely remove the radiator hoses. On some cars, you'll need to remove the heater bypass hose also. Disconnect the battery.
Disassembly
Loosen the bolts securing the alternator and power steering pumps and remove the belt(s). Remove the alternator and power steering pump. If the the AC compressor is bolted to the head being removed, removed those bolts also. Do not completely remove the compressor. Just set it aside. Disassemble the intake assembly. Disconnect the throttle cable and transmission kickdown cable, if the car is so equipped. If working on a front wheel drive car, place the jack, with the block on top, under the front of the engine and take tension. Remove the bone mount arm.
Top End Disassembly
With the accessories out of the way, you need to remove the intake manifold. There are between eight and 16 bolts, depending on engine size. Remove them all. Label and remove all vacuum connections. Pry out the intake manifold carefully.
Exhaust Disassembly
You will need a good penetrating oil like WD-40 for this step. Liberally coat the manifold and lower flange bolts. Remove the lower flange bolts and allow the exhaust pipe to rest on the ground. The exhaust manifold will have between four and ten bolts. Remove them.
Remove the Head(s)
You will need to remove the valve cover(s) to gain access to half of the head bolts. Remove them from the middle to the back and then middle to front, to limit warpage. Carefully remove the head and take it (or them) down to the machine shop for decking and any other work needed. Using the straight edge, check the condition of the block. If there is any space between the block and the straight edge, the block will need to be decked.
Reassembly
This is where the motor manual is needed. Install the new gasket and lower the new head over it. Push solidly down to mate it properly and, using NEW head bolts, tighten them per the torque sequence specified in the manual. Install the exhaust manifold and install the bolts from center to front and back. Torque bolts per specifications. Install the intake gasket and lift the intake in place and torque per sequence and torque specification. Reconnect vacuum lines and air intake assembly. Reinstall accessories, belts and hoses and torque properly. If the car is front drive, reinstall motor bone mount. Fill with coolant and check for obvious leaks.
If you follow the above instructions, you will have successfully changed the head gasket(s) on your car’s engine.
