Intermix is not the oil cooler - now what?

[seningen]

Originally Posted by Doug427

I'm reasonably confident I got it right. I was super careful. As for flushing - it went sort of like this. Completely drain the system - remove drain plug, disconnect two main radiator tube hoses and heater hoses back by the engine, drain thoroughly. Heater core valve was opened prior to all this. Run garden hose through all hoses, in both directions, until water runs clear. Hook everything up, fill with water using vacuum fill tube. Bring car up to temp, drive it for about one hour. Bring home, and do it all again as described above.

Next day, bring car up to temp, and drive again for another hour. Drain and flush again as above. Refill with water and Prestone flush with oil degreaser. Again, filled with vacuum refill tool, as always. Bring to temp and drive multiple times for about 90 min total. Completely drain and flush with clean water until all runs clear. Refill using vacuum refill tool with distilled water and pink coolant, 50/50 mix.

I thought I was done. I guess not.......

It’s likely a crack in the head right around the spark plug.
As the head heats up the crack expands and the oil pressure is
greater than the water pressure and thus you can have a one way intermix.

Mike