As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION, FOUND EXHAUST STAINING IN HOSE FROM HEAT MUFFLER TO ENVIRONMENTAL PACK. REMOVED TAIL PIPE AND PRESSURIZED. FOUND TO BE LEAKING UNDER FINS ON HEAT EXCHANGER. POSSIBLE CAUSE IS NORMAL AGE/WEAR. RECOMMEND MAKING THIS A 500-HOUR ITEM. NOTE: HEATED AIR DOES NOT MIX WITH PRESSURIZED AIR UNDER NORMAL CIRCUMSTANCES, BUT SHOULD NOT HAVE CARBON MONOXIDE PRESENT IN ANY PART OF SYSTEM.