So replacing the o rings all round as part of a renovation, back coolant pipe popped off with little or no effort, the front on the other hand wont come loose.

Thus far I have tried

• undoing and removing both retaining bolts
• Penetrant
• Removing coolant hose (which fought me every inch of the way)
• prybar
• 2 webbing straps and then using the paddock stands as a lever point
• heating the pipe up to the point the 4 o rings that seal it to the engine were smoking / melting

Its still not moving

I don't know what is holding it, only one of the pipes has any movement, the rest are just solid, I have a hooked slide hammer on order, after that I'm stumped as to how the hell I am going to get this to come out

Any suggestions?