Originally Posted by wee-twin
Use a socket or wrench, preferably six point. Do not use a open end wrench. A little heat on the area around the caps should cause expansion and they should break free. Silver neverseize on the threads upon reassembly.
Neither will fit or work in this case. Thread seizure isn't the issue, it's flooded with oil back there. It's the design of the plug. They did that since new when overtorqued (most all were)