I am attaching the layout as provided to us by GM. Hope that helps. I will say, you probably are looking at a leaking water pump or water pump gasket. There is a test that anyone can do to find a cooling system leak. Here it is: https://www.2carpros.com/articles/radiator-pressure-test
You can borrow the pressure tester from your local AutoZone, Advance Auto, or O'Reilly Auto Parts. I think PepBoys also has a loan-a-tool program as well. So do that, and let us know what you find. We will go from there. Good luck.
Thursday, May 17th, 2018 AT 7:38 PM