Compression Check: Specifications

Compression Check

Compression should not be less than 689 kPa (100 psi) and not vary more than 25 percent from cylinder to cylinder.

If one or more cylinders have abnormally low compression pressures, repeat the compression test.

If the same cylinder or cylinders repeat an abnormally low reading on the second compression test, it could indicate the existence of a problem in the cylinder in question. The recommended compression pressures are to be used only as a guide to diagnosing engine problems. An engine should not be disassembled to determine the cause of low compression unless some malfunction is present.