E46Fanatics - View Single Post - Spark Plug Removal
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Old 01-07-2020, 08:07 AM   #25
shadetreemech
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Join Date: Feb 2017
Location: tennessee
Posts: 237
My Ride: 325ci
My two cents - YMMV. Some Ford V8's have a 'spark plug ejection' problem do to a design oversight. When removing the plugs at the recommended service interval the aluminum threads in the head are damaged. Even though the new plugs are torqued properly the threads are weakened enough to 'pull'. After leaving the shop the plug flies out of the head - with the aluminum threads. BMW's do not suffer from this. The relevant point is Ford insists the plugs be removed with the engine hot. Some DIYers go so far as to change one plug a day after driving home from work.

On spark plugs that have compression type gaskets - like BMW uses - if you use anti seize on the threads do not use a torque wrench. Torque them with the 'angle method' described by the plug manufacturer. You will not over tighten them this way. For 'tapered' plugs without a compression gasket- like Ford uses - you must use a torque wrench with nothing on the threads. If you over tighten those on a Ford head you have a high risk of damaging the threads in the head.
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