The internal combustion engine in todays family sedan or minivan still works on the same principles as the Model-T Ford of the early 20th century. However, achieving that combustion process has changed significantly. The single greatest change, beginning in the 1980s, has been by the use of computers to operate and monitor each cycle of the process. Cars are designed to be more reliable, run cleaner and more efficient, and last longer than ever before. Gone, are the days of the tune-up and the shade tree mechanic. Todays automobiles are an amalgamation of very complex systems. Technicians spend hundreds of hours in classrooms and on-the-job- training to become certified in the various systems.
Basic engine maintenance still consists of fresh, clean fluids and clean filters. Developments in lubrication technology, such as synthetic oil, oil additives, and various viscosity grades have greatly improved the efficiency and lubricity of engine oil. However, oil still degrades and looses its effectiveness with usage. A general rule of thumb is to change the engine oil every three thousand miles. Some types of engine oil may last five to seven thousand miles before it becomes necessary to change it. However, dirt and contamination is the mortal enemy of internal, moving parts. It may be necessary to change the oil filter more often.
The combination of burning gasoline at high temperatures and steel parts sliding against one another at high speeds naturally creates a lot of heat. Todays engines run at higher revolutions per minute (RPM) and higher temperatures. The engine oil absorbs and disperses some friction heat created by moving parts. Engine coolant, consisting of a solution of water and ethylene glycol, removes heat from the engine block, and cylinder heads. Ethylene glycol will oxidize and leave deposits on the walls of the engine block. Periodically power-flush the coolant system with a cleaner, such as borax, to remove deposits and rust scale.
Many break downs and unscheduled repairs are caused by electronic component failure. A majority of the electronic components prone to failure are associated with the elaborate emission control systems mandated by the US government. The computer that operates and monitors these systems is called the engine control module (ECM). The ECM may monitor as many as twenty-five to thirty different sensors. Whenever a sensor reads out of its preset range, an error code is set by the ECM. This causes the malfunction indicator lamp (MIL), also known as the check engine light, to illuminate. A technician uses a diagnostic computer to read and interpret the error codes. Many times the repair is as simple and relatively inexpensive as replacing a sensor. Early detection and repair of any problem is essential to the engines longevity. Never leave the MIL illuminated for extended periods of time because of a minor problem. If a major malfunction should occur with the MIL already illuminated, its first indication may be a breakdown at the most inconvenient time possible. With proper care and maintenance, an engine should provide reliable service for more than three hundred thousand miles.