I checked my Beetle this morning before heading off to work... found that the oil was 1 quart below MIN on the dipstick. So, I added Delvac 1 to bring it up to spec.
Do you think I caused any damage with the oil underfilled?
I think in a past post you stated that this was a TDI Beatle. If you had the oil changed at the Dealer, they probably put in Castrol, then you added Delvac I. If it were my auto, I would change the oil, send in a sample for analysis, and fill the whole crankcase with Delvac I, as that seems to be your choice of oils anyway.
Gas or diesel, running 2 quarts low is not the best on a 4-1/2 qt. system. Without analysis you won't know. The problem is you didn't take it back to the Dealer, so now you have no documented record of their error, and it is your word against the Dealer, and they will win. An analysis will either make you happy or madder than heck at this point. But the analysis will give you a record if nothing else. It is easy to say that it didn't hurt the engine because it is running alright, but 40K down the road, out of warranty, and the engine reguritates on the side of the road and we wonder why. IMHO