ENGINE FIRES

SUMMARY OF INFORMATION FROM MANUFACTURER: GM ALLEGES THAT IN ONE INCIDENTA BUS BUILDER IMPROPERLY MOUNTED THE COOLANT RECOVERY BOTTLE, RESULTINGIN ETHYLENE GLYCOL COMING INTO CONTACT WITH AN EXHAUST MANIFOLD ANDIGNITING. THE BUS BODY BUILDER DENIES THE ALLEGATION. IN ADDITION GMIDENTIFIED TWO CHANGES WHICH MAY RELATE TO THE SUBJECT. BEGINNING IN MAY,1983 THE POSITIVE BATTERY CABLE ON "G" MODELS WAS RE-ROUTED AND ADDITIONALPROTECTION INSTALLED. ALSO EFFECTIVE FEBRUARY, 1985 THE ANTI-DIESELINGWIRE WAS SECURED TO INSURE THAT IT WOULD NOT COME IN CONTACT WITH A GROUND.ANALYSIS: ANALYSIS INDICATES THAT THE ENGINE FIRES CAN BE ATTRIBUTED TO AVARIETY OF POSSIBLE CAUSES, AMONG THEM BEING A LACK OF, OR IMPROPERMAINTENANCE, GROUNDING OF A "HOT" WIRE, COOLANT CONTACT WITH THE EXHAUSTSYSTEM, AND POSSIBLE FUEL LEAKS. IN ADDITION TO GM, EIGHT BUS BODYBUILDERS WERE CONTACTED FOR INPUT ON THE PROBLEM. OF THE EIGHT, THREEREPORTED FIRES INVOLVING SIX BUSSES OVER A SIX YEAR PERIOD. AVAILABLEDATA FOR ALL SIX FIRES HAS BEEN REVIEWED FOR ANY POSSIBLE PATTERN OFFAULT OR DEFECT. THREE OF THE REPORTS DID NOT INCLUDE ANY PROBABLE CAUSEOTHER THAN ENGINE FIRE OF UNSPECIFIED ORIGIN. THIS IS PROBABLY A RESULT OFTHE DIFFICULTY IN IDENTIFYING A FAULT AFTER THE FIRE HAS CONSUMED MANY OFTHE INVOLVED COMPONENTS. IN THE OTHER THREE INCIDENTS, DIFFERENT PROBLEMSWERE ALLEGED TO HAVE CAUSED THE FIRES, WITH NO COMMON CAUSE NOTED. INFIVE OF THE SIX INCIDENTS, MENTALLY AND/OR PHYSICALLY HANDICAPPEDCHILDREN WERE ON THE BUS AT THE TIME OF THE INCIDENT. IN EVERY INCIDENTEVERYONE WAS EVACUATED SAFELY WITH NO REPORTED INJURIES. GENERALLY SOMETYPE OF WARNING WAS GIVEN IN THAT THE DRIVER WOULD SMELL SOMETHING BURNINGOR DETECT SMOKE.PROPOSED ACTION: CLOSE THIS PE. THE AVAILABLE MATERIAL INDICATES THAT THEENGINE FIRES CAN BE ATTRIBUTED TO A VARIETY OF POSSIBLE CAUSES. THERE ISNO APPARENT COMMON PATTERN OF DEFECT AT THIS TIME. CONTINUE TO MONITOR THESCHOOL BUS INDUSTRY FOR FUTURE INCIDENTS.===