F 450 2WD Super Duty V10-6.8L VIN S (1999)
Spark Plug: Service and Repair
REMOVAL
CAUTION: Mark spark plug locations and return to original location.
1. Remove the ignition coil.
2. Remove the spark plug.
3. Inspect the spark plugs for bridged gap.
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Check for deposit build up closing the gap between the electrodes.
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Caused by oil or carbon fouling.
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Clean the spark plug.
4. Inspect for oil fouling.
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Check for wet black deposits on the insulation shell bore electrodes.
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Caused by excessive oil entering the combustion chamber through worn rings and pistons, excessive valve stem-to-guide clearance, or worn or
loose bearings.
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Correct oil leakage concern.
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Replace the spark plug.
5. Inspect for carbon fouling.
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Identified by black, dry fluffy carbon deposits on insulator tips, exposed shell surfaces and electrodes.
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Caused by a plug with incorrect heat range, dirty Air Cleaner, too rich a fuel mixture, or excessive idling.
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Clean spark plug.
