Vehicle engines normally have around 150 lbs. of compression. Each cylinder should have close to the same compression levels. Proper compression will result in an automobile that starts and runs well. Low compression, however, indicates problems within your engine that need to be addressed.
Low compression in just one of the cylinders informs you that one of your exhaust valves has probably gone bad. If low compression occurs in two cylinders that are side by side, this usually indicates a failed head gasket. Your problem is with worn cylinders if low compression is occurring in all of them.
Engine compression problems can be tested for using either of two methods. A compression gauge will allow an individual to check engine compression by hand. An engine analyzer is a device that reads the differences in the cranking speed of your engine to determine the compression of its cylinders.
When buying a used vehicle, worries often arise due to the lack of information regarding the condition of its engine. When in doubt, a compression gauge can be purchased for under $40, as of 2011, and will indicate the general condition of the vehicle's engine.
