07-31-2015, 12:40 PM
I think I would do a cylinder leak down test. But you need an air compressor and also the leak down tool. But, that will determine why the compression is low. Leaking past a valve, past the rings, or past a head gasket. That's a common diagnostic test most shops would perform to determine the source of low compression in a cylinder when it is not obvious.
Regards,
Mike
Regards,
Mike