racerkyle88

i did a compression test on my 2003 mustang mach 1 it has about 130,000 miles on it. dry test i got results of 140-145 all the way around. on the wet test i got results of 160-175 all the way around. does anyone know what the spec should be per cylinder. according to a ford tech ford company never put out a actual spec per cylinder and he said he thinks it should be around 200-220. i think thats a little high. does anyone know for sure? thanks

petrock

Compression will start to go down the first time the motor is run, and continue to go down as the miles tick on. So there is no way to accurately provide a spec. It may have been 200-220 when it rolled off the assembly line, but 130k miles will lower that. The numbers you have look good to me. The key is that they are all within about 10% of each other, which they are in your case.

Good luck...