Heat OR penetrant will aid the removal. If you heat it above the boiling/vaporization point of the penetrant, wait for it to cool and then add the penetrant.
Agree, but not too cool as the heat in the manifold will help draw the penetrant in.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
