My Anger Meltdown over Service Dept.

To defend myself, this is their second service department manager in less than a year. I was told the previous manager did not get along with the customers. Evidently, this one doesn't either.

You just dug your hole deeper. Why do you feel the need to defend yourself if all you were doing is asking a few questions? The first person to get angry is typically the loser in any unpleasant situation and you clearly demonstrated that it was you. A second service manager in a year has absolutely nothing to do with your issue, in fact it could portray that dealers desire to get a good manager and not just go with somebody marginal or, of course, the previous manager might have just moved on. You don't know that and it has nothing to do with your issue. So, you learned your lesson and next time you do something else to drain the tanks, that takes all of five-ten minutes, is very easy, and clearly is a owner level maintenance issue.