2nd Gen New member, new to Mini's. Need help with identification

Hello all, I am new to this forum, and new to the life with a Mini Cooper. I bought a 2009 Mini Cooper S, automatic trans 2 door hatchback for my daughter. I love the vehicle, but got a check engine light and getting a code for a thermostat housing and temp sensor. Changed the housing, and the crossover engine coolant tube, but the o ring on the crossover pipe to the water pump is leaking. I ordered a new o ring from Auto Zone and the one I got is not the same number as the one I had researched in other threads and posts. Apparently from what I can gather, the o ring part number I found online is always listed as a 11537548651. The Fel Pro number I bought at autozone says it replaces number 11537548657, and lists all the engine codes it is compatible with, being N12B16A, N14B16A, N14B16C, N16B16A, and N18B16A engines. I have looked on the data plate on the car, and I don't see an engine code listed. So, if anyone can help me to identify if I should have one of the engines listed above, and if anyone has had the same problem, will the 657 o ring work instead of the 651, or do I just definitely need a 651 o ring. I appreciate any help anyone can provide, because I have taken everything apart twice and don't want to take everything back out and in again if I will have the same problem. I would rather not be taking everything out and putting back in a couple more times if I can help it. Thanks for all your help!!

 

Thanks for the warm welcome, and letting me know what engine she has. I actually ended up contacting the BMW dealer in Charlottesville to order the O ring. I had found the one I have is for the thermostat housing side, not the crossover tube. I was reading posts and everyone basically said what you all said, and that was get genuine parts... The tube is ok, but the O rings are crap. Hope when they get here I can get it changed and it won't leak anymore. I will keep you all updated.