I have a 97 740il and one of the tanks has "imploded" and began to leak. Several weeks before I began to heard a "tin can being crumpled" sound which I could not find. I found out that this was caused by a tank vent becoming stopped up. Anyone had this problem?

I have a 97 740il and one of the tanks has "imploded" and began to leak. Several weeks before I began to heard a "tin can being crumpled" sound which I could not find. I found out that this was caused by a tank vent becoming stopped up. Anyone had this problem?
I am having the same type of problem. What did you do to get the problem fixed?