97 F 150 with 4.2 engine I had Jasper long block installed 11000 mi ago to replace hydrolocked original engine. I am now losing coolant again with no visible leaks bubbles milky substance inside the oil cap. The oil looks good. What gaskets should have been used when they installed the old intake on the Jasper engine and if they did if they cleaned the manifold proper.Five thousand dollars and 11000 miles later seems like the same problem.

 

Take it back to whoever installed it and is servicing the warranty and get it looked at.