The head gasket is one of the most important gaskets within an automobile's engine, sealing the place where the engine block and cylinder and preventing the mix or contamination of coolant. A blown head gasket can cause minor problems in some cases---and can be disastrous in others. When the early signs of a blown head gasket appear, it is best to address the problem right away before it becomes more serious. A failing head gasket can often be identified by careful observation of the engine's performance.
If one or more cylinders experience compression loss, the vehicle's performance will change noticeably. If the loss of compression is severe enough, the engine will lose power and fail to perform at peak capacity. In vehicles large enough to require a 6.9-litre engine, this will reduce or eliminate the vehicle's ability to tow, haul or otherwise perform its duties. Less severe compression loss can result in a hissing or tapping sound coming from the engine. Visually examining the engine may reveal the location of an air leak from a blown head gasket.
Overheating and Coolant Links
If an engine overheats and leaks coolant, this may be a sign of a blown head gasket. Visual inspection of the engine can reveal the location of the leak to help determine the cause, be it a blown head gasket or something else, and serve as a guide for repairs. If the location of a coolant leak cannot be determined with the naked eye, an ultraviolet dye test kit can be used to locate it.
Contamination of Fluids
If the head gasket fails to contain an engine's coolant, contamination of the coolant and other fluids can occur. Coolant may leak into the engine's cylinders and cause a cloud of white-blue smoke to appear in the exhaust. Coolant may also appear mixed with the vehicle's motor oil, turning the oil light tan and affecting its texture and consistency. Oil may also contaminate the coolant, and cross contamination is common when one of these two fluids is found mixed with the other. Air can also contaminate the coolant, leading to overheating and a loss of coolant without any obvious sign of a leak.