2012 3.7 V6 water pump - what's the trick?
 

My water pump bit the dust at 144k miles, and I replaced it with a new Murray unit. The pump is easy to change and uses a metal gasket with a glued-on rubber seal on both sides. There is also a new O-ring in the pump that slides over a fitting on the block. The problem is, it leaks. I thought the metal/rubber gasket was bad, so I took the pump back for another one. The second one still leaks. There was no gasket residue to clean, but I made sure all surfaces were clean, dry, and undamaged. I was careful to tighten the bolts in a correct an even sequence. It still leaks from somewhere around the body of the pump, and not the shaft. This pump fits twenty different Ford models. Has someone out there successfully changed this pump? What did you do to keep it from leaking?

Part number CP6654 looks like the right one. 'Maybe' you messed up the gasket? They also sell gaskets 'separately' if its messed up :)

I thought about that. Maybe I got it too tight. It's just a rubber gasket.

There is a TSB out for these cars recommending a check valve be installed in the cooling system. The TSB appears to say that air in the system will make the water pump leak. I fail to see how that is possible if the shaft seal and gasket are doing what they are supposed to do.

Maybe.......With an air pocket in the water pump it makes the bearing overheat and fail. This is what i think could happen :)