NHTSA Complaint #723850 — 1993 LINCOLN MARK VIII

BOTH CYLINDER HEADS FAILED WITHIN ABOUT 5,000 MILES OF EACH OTHER. THE FAILURE IS SPARK PLUGS BLOWING OUT OF THE CYLINDER HEAD, TAKING THE THREADS WITH THEM. FOMOCO RECOMMENDS SPARK PLUGS BE CHANGED AT 100,000 INTERVALS. HERE IS THE PROBLEM: MECHANICS UNDERSTAND THAT AN ALUMINUM CYLINDER HEAD AND STEEL SPARK PLUGS CAUSE A DISPARITY. THE CONSTANT HEATING AND COOLING OF THE CYLINDER HEADS OVER 100,000 MILES CAUSES THE STEEL SPARK PLUGS TO PARTIALLY BOND TO THE ALUMINUM THREADS IN THE HEAD. WHEN THE OLD PLUGS ARE REMOVED, THEY EXTRACT A PART OF THE CYLINDER HEAD THREADS AT THAT TIME. NEW PLUGS ARE THUS INSTALLED ONTO WEAKENED THREADS. EVENTUALLY, THE THREADS GIVE WAY AND THE PLUGS EXPLODE OUT OF THE HEAD. IN MY CASE, THIS OCCURRED ABOUT 25,000 MILES AFTER THE PLUGS WERE CHANGED. I DON'T FEEL OBLIGATED TO FUND REPAIRS TO A DESIGN DEFECT IN THIS ENGINE. THIS ENGINE SHOULD NEVER HAVE HAD EITHER HEAD FAIL, MUCH LESS BOTH OF THEM. TO ADD INSULT TO INJURY, THE SECOND HEAD BLEW AT THE NORTH CAROLINA-VIRGINIA BORDER ON INTERSTATE 85 (VIRGINIA WELCOME CENTER). SINCE A MARK VIII CAN ONLY BE WORKED UPON BY A LINCOLN DEALER, I HAD TO PAY A 135 MILE WRECKER BILL TO TRANSPORT THE CAR TO THE NEAREST LINCOLN DEALER IN PORTSMOUTH, VIRGINIA. *AK