[eystein]

Checked the anti freeze at the top of the radiator and to my surprize it was only holding down to +5 deg F. So I decided to drain off some coolant from the drain cock at the bottom in order to make room for filling more anti freeze, but to my surprise I saw that the half gallon that I drained off was deep blue in color. When I measured the freezing point of what I drained off at the bottom, I discovered it was good for -58 deg F.

I then poured what I drained off at the bottom back at the top of the radiator.

The car then sat for two weeks, and now its the same story again. -4 deg F freezing point at the top of the radiator and -58 deg F at the bottom.

How can this be? Does the anti-freeze separate from the water over time and can the engine freeze up at the top while it is protected at the bottom.