What was found
(CAN) PILOT PARKED THE AIRCRAFT BECAUSE OF OIL LEAKING AND RT ENGINE RUNNING ROUGH. THE RT ENGINE NR4 CYLINDER WAS FOUND TO HAVE A BROKEN INTAKE PUSHROD, BROKEN EXHAUST PUSHROD AND BROKEN PUSHROD TUBE THAT CAUSED OIL TO LEAK FROM ENGINE. IT WAS FOUND THAT BOTH PUSHROAD TUBES WERE SLIGHTLY DENTED CAUSING THE PUSHRODS TO RUB AND OVER TIME WEAKEN AND BREAK. WHEN THE PUSHRODS BROKE THEY PUNCHED HO LES INTO THE PUSHROD TUBES AND OIL LEAKED OUT OF THE ENGINE.THE ENGINES ARE INSTALLED VERY CLOSE TO BOTTOM COWLINGS, BOTTOM COWLINGS ARE NOTREMOVABLE MAKING IT VERY DIFFICULT TO WORK WITH HAND TOOLS.