4.7 Motor going thur antifrezze every 1000 miles about a gallon ? No leaks out side of the motor... Had Heatercore replaced.. Update motor had bad headgaskets !!!!

I had to use a big piece of cardboard under the front of one of mine to see because it was parked on gravel. I got under after shutting it off hot to see where it was leaking from.

Is it smoking out the tailpipe? Have you checked the oil to see if its a milky color? could be a head gasket.