2003 FORD NAVIGATOR Engine And Engine Coolingengine Problems

03 NAVIGATOR BEGAN "STUTTERING" WHEN DRIVING, FELT LIKE A TRANSMISSION SLIPPING. I TOOK IT TO THE DEALER AND THEY SAID THREE OF THE EIGHT CYLINDERS WERE NOT AT FULL COMPRESSION. HE ADVISED NEW HEADS WERE NEEDED. COST: $7000. SEVERAL SERVICE BULLETINS HAVE BEEN ISSUED ON THE PROBLEM, INDEPENDENT (FORMER FORD TECH) MECHANIC LOOKED AT THE PROBLEM. HE ADVISED THIS IS VERY COMMON ON THE TRITAN MOTOR AND THERE IS A CASTING PROBLEM WITH THE HEADS. *TR

2003 FORD EXPEDITION XLT WITH 5.4 LITER TRITON V8 ENGINE WITH 59,000 MILES. THE VEHICLE IS WELL MAINTAINED AND NOT ABUSED. THE #3 SPARK PLUG WAS BLOWN OUT OF THE ALUMINUM CYLINDER HEAD DURING DRIVING AT APPROXIMATELY 5 MPH. THIS EVENT WAS PRECEDED BY A TAPPING NOISE WHICH OCCURRED OVER THE PRECEDING TWO WEEKS. THE NOISE WAS SIMILAR TO A NOISY VALVE LIFTER. THE ENGINE HAD THE ORIGINAL FACTORY INSTALLED SPARK PLUGS THAT WERE NEVER REMOVED, REPLACED OR SERVICED. THE FACTORY CHANGE INTERVAL ON THE PLUGS IS 100,000 MILES. SPARK PLUG BLOW OUT RESULTED IN THE THE NEED TO REPLACE THE CYLINDER HEAD AND COIL PACK. INSPECTION OF THE OLD PART REVEALED THAT ONLY 4 TO 5 THREADS WERE PROVIDED TO RETAIN THE SPARK PLUG. INSPECTION OF THE NEW REPLACEMENT HEAD REVEALED THAT 9 THREADS ARE PROVIDED TO RETAIN THE SPARK PLUG. FORD KEPT THE OLD PARTS. THIS IS AN...