Originally Posted by 74C5
Heat can be your friend. Torch around the screw and give it a shot while the case expands before the screw does. Worst case, capillary action may drive the penetrating oil into the threads.
Like He Said!
Heat - properly applied will probably solve this! Often it is as simple as riding it, getting it up to normal temperature and trying to loosen before it cools off. Heating with a torch is also a plan, provided you are dilligent about heating the right part to the right temperature, you do NOT want to heat and expand the plug - it's the case around it that needs to be gently heated. A bit that fits the slot correctly is usually the first thing that gets overlooked, 'Close Enough' ISN'T! A loose fit can be improved with a touch of valve grinding paste or the bit could actually be glued into place before you try loosening.
No one calls the Fire Department because they did something smart!
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