A C414 IN CRUISE AT 11000 FT SHUT DOWN THE L ENG DUE TO HIGH OIL TEMP CAUSED BY A DEFECTIVE ENG OIL TEMP BULB.

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AFTER DROPPING PAX OFF IN DESTIN; FL; I RETURNED HOME TO LAFAYETTE; LA. INITIAL CRUISE ALT WAS 14000 FT. EVERYTHING WAS WITHIN PRESCRIBED PARAMETERS UNTIL ABOUT 100 MI E OF LFT. OIL TEMP ON L ENG BEGAN TO CREEP UP. I REDUCED PWR ON L ENG; OPENED COWL FLAP; ENRICHED MIXTURE. ALTHOUGH EGT; CHT; AND OIL PRESSURE RESPONDED NORMALLY; OIL TEMP CONTINUED TO RISE. ABOUT 30 MI FROM ARPT; OIL TEMP RED-LINED; DESPITE ALL EFFORTS TO CTL IT. I FELT IT PRUDENT TO SHUT DOWN THE ENG IN A PRECAUTIONARY EFFORT TO PREVENT CATASTROPHIC LOSS OF THE L ENG. SINCE ALL OTHER INDICATIONS WERE NORMAL; I SUSPECTED A BAD SENDING UNIT. SINCE THE OIL TEMP RISE WAS GRADUAL; IT DID NOT SEEN TO INDICATE A SHORT. THE SHUTDOWN WAS STRICTLY PRECAUTIONARY. I WAS NEAR THE ARPT AND THERE WERE NO PAX ON BOARD. I DID NOT REQUIRE SPECIAL HANDLING AND DID NOT DECLARE AN EMER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE HIGH OIL TEMP WAS CAUSED BY A MALFUNCTIONING ENG MOUNTED OIL TEMP BULB. THE RPTR SAID THE L ENG OIL TEMP SYSTEM WAS SUSPECTED TO BE A FALSE READING BUT IF IT WERE PROVED TO BE CORRECT THE ENG WOULD HAVE INCURRED SEVERE DAMAGE BY CONTINUOUS OP.