Probably 216, but could be an early 235 (measuring the bore will confirm), but that really doesn't matter for the problem at hand. Not all penetrating oils work the same... My go-to is Kroil, but frankly, a 50/50 mix of ATF and Acetone probably works as well. Just be carful with the Acetone, if you use that, since it is very flammable. Some gentle persuasion with a wood block and hammer - in both directions - may help, also.
Sometimes it just takes a long time to work, so patience is another necessary ingredient.
Hope this helps.
Doug
