I have an 05 Camry. My wife was driving it and said the AC wasn’t working and needed recharging. I had just used it in the morning and it was fine. I took it for a test drive and the AC pumped out cold air off and on and the temp gauge was half way, where it should be. A few more minutes of driving and the AC wasn’t sending out cold air any more and the temp gauge said it was hot. Also the check engine light was on, but I don’t have a code reader, so not sure what it was saying. I went a few blocks to home, and checked the coolant, and the overflow reservoir was empty, even though when I checked it a few days ago it was full. Nothing was leaking under the car. I filled it up, started up the car, ran it for a few minutes and all the coolant was gone again.
I suspected that I needed a new thermostat, but have never changed one before. I looked up how to do it and how to diagnose it. The car had cooled down by then. Looked in the radiator and I can see coolant to the top. Started up the engine and now I’m getting cold air out of the AC and the temp gauge is half way again. However, the coolant overflow tank is empty again, yet nothing is leaking. The radiator cap never got hot after running it for about 10 minutes in the driveway, but the upper radiator hose was hot and the bottom was warm. And now the check engine light was off. Seems like the thermostat was working again.
Does this sound like a bad thermostat, that is now temporarily working? Anything else I should check or should I just replace it?