the factory ford stuff should be a anti-cavitiation antifreeze also, they used that even back with the 7.3. if a modren diesel doesnt have it I would be surprised, or suspect some one who didn't know better changed the antifreeze and put the wrong stuff in it.
what did the old impeller look like, do you have a side by size comparison of the two impellers?
I posted a waterpump replacement video a couple months back. I show the old pump and take several measurements of both old and new pumps and impellers.
I have found a waterless antifreeze that was featured on Leno's Garage and Project Farm. It's non waterbased and doesn't boil until 260-280 degrees. It has strong resistance to cavitation. I think it is EVANS costing about 50.00 a gallon. They say it doesn't expand when hot like water-based coolants. I'll have to rinse out the old antifreeze from the engine to make the change. The waterless stuff will tolerate up to 3% water.
The waterless coolant may be the cure I'm looking for.
