L28 NA N42 Engine (Block and head)

Thanks all,

Confirmed blown head gasket over multiple cylinders. All piston tops steam cleaned on the intake side of the head.

First pic is piston #6 how the piston top should look on a high mileage engine, covered in carbon deposits. Second pic is piston #3 nice and clean with drops of coolant on top. #3 was also the lowest compression reading at 150 PSI. It gets worst #4 and #2 have small portion of the piston top cleaned as well, all on the intake side. So the entire center section of the gasket failed. 

Confusing how all the test I ran where negative to coolant in the oil, carbon dioxide in the coolant. So where did the milky foam go? In my catch can venting the valve cover and block, the dreaded milky foam was present when I opened the valve :(. The engine starts and runs fine, not smoking????????????

Open the wallet and rebuild.