Well, these bolts in the cooling channels are fun!. I have one though that is so rusted i cannot get a good purchase with the 12mm 12-point socket. Any idea's?
I was thinking of heating an 11mm 12-point up, putting it over and waiting for it to cool, would this work?

Poo picture i know but hey...

 

What you need I a special round but extractor Im a mechanic and use the quite often I wouldn't try heating up a socket there are likely to shatter.

 

gotta go imperial mate

 

stick some diesel in it and leave it over night.

 

If the bolt heads are badly corroded, just drill the heads off - you will then be able to split the crankcases and undo the shank of the bolt by hand.

Mick