NHTSA Complaint #10178546 — 1994 BMW 740I

1994 740I BMW LEAK DOWN PROBLEM THAT DESTROYED THE ENGINE**CC THE LEAK DOWN FLAW CAUSED THE ENGINE TO DEVELOP WORN LININGS AND EXHIBIT A ROUGH IDLE. THE CONSUMER STATED THE MANUFACTURER USED NIKASIL, AN ALUMINUM, NICKEL AND SILICON ALLOY TO LINE THE CYLINDERS OF THE M60 ENGINE. THE CROSS HATCHED NIKASIL LININGS REACTED WITH HIGH SULFUR CONTENT FOUND IN LOWER-QUALITY GASOLINE. THE REACTION CAUSED DAMAGE TO THE VERY TOP OF THE CYLINDER BORE, WHERE THERE IS MOST CONTACT OF THE BURNING MIXTURE AND THE CYLINDER LINING. THE DAMAGE PREVENTED A GOOD SEAL FROM FORMING BETWEEN THE PISTON AND THE CYLINDER WALL, WHICH CAUSED A LOSS OF COMPRESSION IN THE COMBUSTION CHAMBER. THE CONSUMER STATED THE ONLY PERMANENT FIX FOR THE PROBLEM IS TO REPLACE THE SHORT BLOCK WITH THE EQUIVALENT BLOCK USING ALUSIL LININGS, WHICH DO NOT EXHIBIT THE CORROSION PROBLEM. *JB