temp gauge goes up to normal and then goes down to o then goes back up.open radiator after driving low pressur

look at wireing to gage under hood is good place to start.

Your gage sounds bad. The car might be fine just the gage is out of whack. If you have one of those home testers for your car like the ones they sell at parts stores might want to check that. Check all your hoses give them a squeeze see if there tight or soft. you want tight. That is really a question for a mechanic in my opinion.

sure, undesirable Thermostat. it extremely is caught OPEN or it extremely is lacking thoroughly and not permitting the engine to maintain the required temperature. This will additionally reason you to have undesirable mileage because of the fact the engine thinks it continuously desires greater gasoline. replace the Thermostat and save money and income overall performance.

Symptoms do sound like intermittent fluid flow past the tempurature sensor, or a faulty sensor. but you are right to susptect low anti-freeze levels. To your very reasonable list of things to check, please add look for a bad thermostat, or a flaky waterpump.

Air is possible but more like sticky thermostat.