I haven't tried running the engine first, as it seemed to me that the parts would expand with heat and become even harder to remove, but it sounds like you really need the heat to free a seized part.
WD-40 hasn't done the job so far. I noticed that there are some other products on the market that are supposed to be more suited to this specific purpose.
Here's a list of ones I've read about
:
"Loosen Up™ Penetrating Oil
http://www.wellworthproducts.com/pro...enetrants.html
Special formulation enables Loosen Up to creep better than ordinary products. Penetrates through rust, grease and dirt to loosen seized parts. Even under the most extreme conditions, special additives guarantee constant lubrication and resistance to high temperature breakdown."
PB Blaster
http://www.pbblaster.com/store/
Liquid Wrench Super penetrant
http://www.gunk.com/item_asp/L104.asp
Marvel Mystery Oil