2006 Boxster 987 cooler problem

[Magdi987]

Dear All, I've experienced a quite strange failure recently, and became very curious about your opinion on this. The long story short: I've found my car with the coolant underneath, and took it to the mechanic. First we thought that the problem was only the rubber gasket, but when the mechanic took out the relevant part (showed in the picture 987 106 508 04) we've seen a small broken edge on the plastic. Strange, because this plastic part is fixed with several bolts, so I think it's impossible to move and brake. Finally the mechanic changed the part, now it works perfectly, just I'm curious what it could be. If you had the same problem, please share your experience. Thanks in advance!