I have cummins triple nickles, they run around 180. After running on shut down they burp just a little glycol is this normal. I have change radiator caps . Not sure what the new or old caps are rated.
David, do you add coolant later to replace what you lost? It's ok to be an inch or two low for expansion. It's possible that you are overtopping and while running the waterpump keeps the level pulled down.