hmmmmmmmmmmmm. I find it hard to believe that the customer could run a car with oil gushing out of the filter housing and not notice a problem, No noise, no knocking, no oil light, no puddle on the floor, no smell or smoke etc. ????

The only way he could manage it would be on a long motorway run and it emptied the sump in a short time on a single run. ??

Could it have overheated and got that hot that the plastic has melted. ?? ( I have a customer with a passat that this happened on, but I think his was because the turbo had self destucted and it drank its own oil. )

Its Easy for a tech to say that you overtightened it, but if they had done the job, then it would just have been caused by a defective cap, If it was overtightened, would it have lasted 3 months. ??

And when was the last time that the customer checked his oil. ?? .... Never. ??

Tony.