Proper Thermostat Performance?

[blacksambo]

Did you replace the water pump when you replaced the timing belt? It's recommended.

I was told in the past (not sure I believe it though) that the fins on a water pump can erode over time/use. If that were to happen though, I'm guessing that it would show the symptoms you describe.

Water pump is original. But maybe I'm dense, but why would less rpm cause lower water temp. to occur? Thx