If there is just a single incidence of trapped air, it should work its way out pretty quickly, I would think. In my case, at first I would need to add coolant every 1500-2000 miles, then it progressively came to the point of needing to add coolant every 500 miles or so. I don't think any was being forced out the overflow, rather small amounts were being burnt. I didn't really notice any difference in the temperature gauge as the problem progressed. Good luck and keep us informed as to what you find out, we are all in this together.

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Keep everything as simple as possible-but no simpler--Albert Einstein