What was found
THE ENGINE WAS UNDERGOING A COMPRESSION CHECK. ALL 4 CYLINDERS HAD GOOD COMPRESSION, 70 PSI, HOWEVER THE MECHANIC PERFORMING THE CHECK HEARD A FAINT HISSING SOUND WHEN THE NR 4 CYLINDER WAS TESTED. THE MECHANIC REMOVED THE INTER CYLINDER BAFFLE AND INTAKE RISER TO THE NR 4 CYLINDER; WHEN HE SPRAYED ON SOAPY WATER, BUBBLES APPEARED ON THE UNDERSIDE OF THE CYLINDER ASSY. IT APPEARS THERE WAS A LEAK COMING FROM THE AREA OF THE CYLINDER WHERE THE HEAD IS THREADED ONTO THE BARREL, THOUGH NO CRACKING, DEFORMATION, OR EXHAUST STAINING COULD BE SEEN.