Any new ideas for the old intake manifold stuck bolt problem?

[Craigar]

 93 Loyale EA82 SPFI

Whilst replacing my water pump etc. I discovered another problem - the right side (by alternator) intake manifold is leaking coolant, which I suspected for a few years.. and the back long bolt is stuck / frozen - and so are the 2 long ones on the passenger/left side also...  I soaked their heads and around the gasket (where we need really need it but probably can't get past the gasket) with liquid wrench and have to take care of other business so it will be a month before I can get back to it.  Read through lots of good ideas for stuck bolts BUT these long intake manifold bolts have the head of the bolt more than an inch and a half from the stuck threads going into the head so I don't think many of those ideas will work. I'm thinking a 6 point impact socket, impact wrench and maybe first drilling a small hole into the manifold close to the base of the bolt, about a quarter inch above the head that I can load up with some fancy "nut buster" sauce, I have liquid wrench from 20 years ago but maybe their is something a lot better now?

Here's some good ones

https://www.ultimatesubaru.org/forum/topic/44039-what-are-my-options-with-this-stuck-bolt/#comment-354824

[Steptoe's photos]

I think I still have an EA82T head stashed somewhere that has a broken and corroded bolt stuck in it - inlet manifold bolt - from 2006 !

[Craigar]

[idosubaru]

I’ve gotten some nasty EA intake manifold ones out like this. But it takes forever. 

Turn the bolt back and forth over and over and over again.  Not to remove jt - Just a few degrees. Just enough to work some of the corrosion loose without yielding of the metal.  After a few minutes take a break (do one of the other bolts).
 

Working it back and forth creates heat which increases the metals ability to deform and lead to shearing of the bolt.  you want to give it plenty of time to cool down. 

Keep repeating that step until you increase range of motion.  Once the head of the bolt comes up enough spray a high grade penetrant down the hole.  I have YIELD.

wash rinse repeat all of the above. 
 

If all the bolts are out but one is drilled or sheared off the head can still be stuck on all the packed corrosion in the bottom half of that hole that goes through the intake manifold.  The sheared/drilled bolt and corrosion are packed tight in the head and will hold it in place. 

if it’s one bolt only you can try to rotate the entire head back and forth to loosen the one stuck area, while prying upward.  If it’s more than one good luck, that’s not easy to drill or pry out if they’re full of corrosion. 
 

[Dwayne Oxford]

Induction heater may help.

[6 Star]

Just like @idosubaru says;

Turn the bolt a little bit, spray the bolt head with PB Blaster or other penetrant fluid.

Then torch the area of the head where the bolt is stuck with a map gas torch (handheld)

Turn the bolt back and forth just a couple degrees again.

Torch the area, spray with PB Blaster or dab on some candle wax while it's still hot. It will make the lubricant soak down to where it's needed.

Keep repeating the process until the bolt frees up