No one enjoys having car problems--even those of us who claim to enjoy working on cars and repairing them. The last thing we want to do is be forced into working on our cars. We can schedule upgrades and maintenance at our convenience, but a car problem means having to drop everything and change your plans to make repairs. Sometimes a car problem can be as simple as replacing a burned out headlight bulb. A quick trip to the parts store or even Wal-Mart and you have part in hand and the job done in a relatively short amount of time. No muss, no fuss, and your weekend of holding the hammock down with your backside is spared. But sometimes a car problem arises that just can't be accomplished this quickly, and though the job has to be done, it is dreaded every minute until the car is running again. Head gasket replacements are right at the top of the list when it comes to dreaded repairs.
A head gasket is no easy problem to diagnose to begin with, and the repair in itself is lengthy, laborious, and quite boring. There's not much you can do but roll up your sleeves and dig in, leaving yourself plenty of time to complete the work.
How do you know if you have a bad head gasket in the first place? Some of the telltale signs of a bad head gasket make it extremely easy to diagnose, while other signs make you get out special tools for testing. Depending upon where the gasket failure occurs on the gasket, you can have a large amount of coolant entering the combustion chamber, which causes billowing white smoke to exit the tailpipe, along with raw coolant (if the failure is severe enough).
Another easy diagnosis is when the gasket failure is between a coolant passage, the combustion chamber, and an oil passage. When this occurs, the cooling system and engine crankcase oil mix, creating a beige soupy substance throughout the engine and cooling system. Removing the oil fill cap, dipstick, or radiator cap, and visually inspecting the contents should immediately tell you if this situation has occurred.
Sometimes, though, the reason behind a bad head gasket is not evident and testing needs to be done to detect the problem. If a head gasket failure is minor, then it may be hard to get to the bottom of things. Small failures can cause overheating and/or coolant loss as well as poor driveability. Testing each cylinder for compression, testing cylinder leakdown, and pressure-testing the cooling system are necessary for an accurate diagnosis.
Our Mustang in ailing health is a '90 GT hatchback. Internally, the 5.0 is bone stock, but the GT does wear a 100hp nitrous kit. The owner isn't sure if the nitrous or a recent high-rpm chassis dyno pull caused the head gasket failure, but we'll tear into the GT and get the owner back on the road in a weekend. All that is needed is a typical set of handtools (which you already should own), fuel line disconnect tools, and the proper shop manual to fill in the blanks.