Ford Repair: spark plug, spark plug thread repair, thread chaser

Question
2000 f-150
blowed a plug. the new plug will not tighten down tight its loose.ran a thread chaser it does not seem to tighten up real snug.what do you thing

Answer
Hi Denise,
         I deal with this all of the time on that engine design. It is probably the third or fouth one back on the pass. side(cyl. 3 & 4). It is a little difficult to do, but NAPA makes a spark plug thread repair kit, it's called Save a Thread. That has been the only way I have been able to fix that. You ream out the hole oversize with the tool provided and install either the long or medium length insert with red Loctite. Install the insert with the plug on it and leave it in there 12 hrs preferrably before starting. You should use a Motorcraft platinum plug so it won't have to be removed again hopefully. Always replace the ignition coil(it always breaks anyway), or that cylinder will misfire. The dealer will always try to tell you to replace the cylinder head ($$$$), but if you can successfully do this , your'e ahead of the game :-) Shaun.