Seized swirl pot filler plug

[skiver.]

As it says; I have tried to unscrew it but the top of the swirl pot began to distort with the pressure.I thought about applying heat to the area but would this just make the aluminium softer and easier to twist out of shape?
Or should I just leave it and bleed the system through the hose at the top of the pot?
Thanks for any advice.

[skiver.]

I should have pointed out that the original brass slotted plug has been replaced with a hexagon socket plug so grip is not a problem. Maybe this non brass plug is more prone to corrosion with the aluminium. I have tried the 'shock' treatment but don't want to split the pot or break any welds so I'll try a little heat on it. Thanks for the info so far.

[skiver.]

bobfather said:

Not in my experience, I had awful trouble every time I had to remove the slotted brass plug. Swapped it for an Allen-key version 8 years ago, never had as problem since then. Where did you get the replacement plug from?

The plug was fitted during a service a few years ago as the brass one was damaged.
I've tried heating it and 'shocking'it again but reached the point where I felt something was going to give, and it wasn't going to be the plug, so I'll play safe and wait until the next service.
I'm going to Le Mans next week and can't risk breaking anything!