F 350 4WD Super Duty V8-6.4L DSL Turbo (2008)
Spark Plug: Testing and Inspection
Spark Plug Inspection
1. Inspect the spark plug for a bridged gap.
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Check for deposit build-up closing the gap between the electrodes. Deposits are caused by oil or carbon fouling.
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Clean the spark plug.
2. Check for oil fouling.
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Check for wet, black deposits on the insulator shell bore electrodes, caused by excessive oil entering the combustion chamber through worn
rings and pistons, excessive valve-to-guide clearance or worn or loose bearings.
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Correct the oil leak concern.
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Install a new spark plug.
3. Inspect for carbon fouling. Look for black, dry, fluffy carbon deposits on the insulator tips, exposed shell surfaces and electrodes, caused by a
spark plug with an incorrect heat range, dirty air cleaner, too rich a fuel mixture or excessive idling.
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Install new spark plugs.
4. Inspect for normal burning.
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Check for light tan or gray deposits on the firing tip.
