What was found
(CAN) UNIT IS CALLED A COFFEE CAN TYPE CABIN HEATER, CRACK ONLY VISIBLE WHEN THE UNIT WAS REMOVED FROM THE AIRCRAFT EXHAUST SYSTEM (C2EE249). THE DEFECT WAS NOTED DIRECTLY BEHIND THE TRIANGULAR AIR DEFLECTOR AT THE AIR INLET TO THE CABIN HEATER. THE CRACK WAS NOT VISIBLE WHILE THE EXTERNAL HEAT SHROUD WAS REMOVED FOR INSPECTION (CF-90-03-R2). RECOMMEND A DETAILED INTERNAL INSPECTION OF THE EXHAUST STACK FOR FUTURE INSPECTIONS OF THIS STYLE OF DHC2 CABIN HEATER.