So, I have screwed up royally. I bought a container of Ad Blue diesel exhaust fluid in order to help my daughter with her 2012 Q7. In the process, I managed to snap the filler cap lug into three pieces. Now she and her husband are mad at me and I can't blame them.

The lug section of this plastic cap snapped into three pieces and underneath I found a circular cap (at least it resembles a cap with what appears to be a breathable filtered center.) This circular cap will not unscrew by hand (looks the same as a gas cap but smaller..... so seems as though I should just be able to unscrew it)........ anyway, it's on too tight.

The last time she and I filled this reservoir was by taking it to the dealer. Could the dealer have tightened the cap too tightly or is it always like this?

Will it be difficult to buy a replacement cap? I'm in Canada.

I feel very badly about this.... Any info and advice appreciated.

Rick