The engine provides the power to drive the vehicle’s wheels. All automobile engines, both gasoline and diesel, are classified as internal combustion engines because the combustion or burning that creates energy takes place inside the engine. The biggest part of the engine is the cylinder block. The cylinder block is a large casting of metal that is drilled with holes to allow for the passage of lubricants and coolant through the block and provide spaces for movement of mechanical parts. The block contains the cylinders, which are round passageways fitted with pistons. The block houses or holds the major mechanical parts of the engine.


Today’s automotive engines can be classified in several ways depending on the following design features:

■ Operational cycles. Most technicians will generally come in contact with only four-stroke engines. However, a few older cars have used and some cars in the future will use a two-stroke engine.

■ Number of cylinders. Current engine designs include 3-, 4-, 5-, 6-, 8-, 10-, and 12-cylinder engines.

■ Cylinder arrangement. An engine can be flat (opposed), inline, or V-type. Other more complicated designs have also been used.


Diesel engines represent tested, proven technology with a long history of success. Invented by Dr. Rudolph Diesel, a German engineer, and first marketed in 1897, the diesel engine is now the dominant power plant in heavy-duty trucks, construction equipment, farm equipment, buses, and marine applications. Diesel engines in cars and light trucks will become more common soon. There are many reasons for this, one of which is that low-sulfur diesel fuel will be available in the United States.


To conduct a compression test on a Ford Escape, you must use a scan tool and the one from Ford is preferred. The scan tool allows you to enter into the engine cranking diagnostic mode. This mode allows the engine to crank with the fuel injection system disabled. It also makes sure that the starter motor/ generator is not activated (except for activating the starter motor to crank the engine),