Interpreting Compression Readings

AllData Editors Note - Ford does not provide a cranking pressure specification, only an acceptable range.





The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75 percent of the highest reading. Refer to the Compression Pressure Limit Chart.

If one or more cylinders reads low, squirt approximately one tablespoon of clean engine oil Motorcraft Super Premium SAE 10W-40 XO-10W40-QP or equivalent meeting Ford specification WSS--M2C153-G on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.