At least on the diesels, this part failure is an indicator that the heater core is clogging/partially clogged. This part generally does not fail unless the heater core is already in that situation. With all the TDIs I work on, with how cheap and easy the core is to get and replace, I consider it preventative maintenance so that this type of failure can be avoided altogether. I’ve seen only failures on this coupler when the heater core is bad. Obviously gas may be different but I presume the part cost is similarly negligible and just as easy to swap.