Replacing a head gasket in a 2001 through 2005 Honda Civic is a lot of work, but if you're handy in the garage, you can save a lot of money by doing the work yourself. Replacing the head gasket requires you to remove all connecting lines and to lift the head out of the engine block. There are plenty of potential pitfalls in the replacement process that you can avoid with a little bit of foresight and planning.
When replace your head gasket you'll need to remove lots of wires and hoses that connect to the main systems, including radiator hoses, ignition wires, cooling lines, and electrical connectors. Be sure to accurately label these wires and lines so that you can later re-attach them in the proper place. It may be helpful to create a large schematic diagram of the engine and label where each line was originally attached.
Double-check to be certain that all connectors and lines are disconnected before you attempt head removal. While this may seem tedious, removing the head with a line still connected will result in additional parts costs and could result in coolant or fuel leaking and fluid spillage. While most of the head gasket change is a one-person job, you may wish to enlist a helper when physically removing the gasket, as it is quite heavy.
After you've disconnected the timing belt, you'll need to disconnect the fuel lines from the intake manifold. Be sure to immediately plug the lines with a fuel line stopper; otherwise your fuel is liable to leak on the engine, on your work surface and on you.
Depending on the condition of your engine, you may experience difficulty when attempting to restore bolts to their proper locations on the block. One way to help facilitate bolt reattachment is to briefly soak your bolts in motor oil before putting them back in. The motor oil will serve as a lubricant for the bolt and is not harmful to your car.
One flaw in the Honda Civic's design is the amount of work required to access the timing belt and water pump. Replacing those two components at or near 115,000 miles is both necessary for continued functionality and quite expensive, given the amount of work needed to access them. You should consider replacing both the water pump and timing belt at the same time as the head gasket. When you replace the head gasket, you've already done all of the prep work required for timing belt and water pump replacement, so replacing those additional components at the same time will save you a great deal of work in the long run.
