I can not get the last (iron?) plug out of my intake mainfold. It has the square head so I can't use a ratchet and I am applying so much force to crescent wrenches and box wrenches that it either spreads the wrench apart or rounds off the head. I have WD/40d both sides and let it soak.

Any ideas for getting this iron plug out of an aluminum threaded hole?

WD-40 is actually a water dispersant and not a good lubricant. Try soaking with a good penetrant like Liquid Wrench or my favorite, PB Blaster. Another trick is to heat the plug with a torch then stick a candle on the threads. Heat will melt and draw wax into the threads and then you can back it out.

sometimes the correctly found sae or metric 12 point socket will fit on there just fine. it'll fit in the square pattern within the socket that way. i always tighten the plug first with a hitting action on the breaker bar. as if an impact was hitting/rapping on it. but tighten it first till it "cracks" loose. it doesn't always get it though. sometimes you get lucky.

also,, you can "warm it up" some by hitting on the plug from above with a metal drift of some sort like a ford kingpin. it'll dislodge the rust and scale enough to let it break free sometimes.

all that is short of drilling it out and die grinding with a carbide till you can see the thread peaks of the manifold itself all the way arround and down the hole,, then peel it out like a heli-coil. a pick will get the end of the leading thread started outward,, then needle nose pliers to twist the rest out. good luck,, hope it helps.

A 14" pipe wrench works wonders. If it's corroded/ rusted and shears the square drive head off the plug, your down to drilling and a carbide bit to 'trim' as much out as you can, then pick the last threads out with a pic, and freshen the threads with an NPT pipe tap. Corky is dead on with the PB Blaster, WONDERFULL stuff.

(edit, LMAO Rat,, great minds think alike, just some type slower than others)

(edit, LMAO Rat,, great minds think alike, just some type slower than others)


two fingering it to pieces are ya?? he he. thanks sir.