My explorer wasn't cooling like i like so I bought some refrigerate and the gage said there was too much already. I have never filled it in the 8 years I have owned it.
Buy 3 cans and monitor it. It may take 3 cans or less. It has to run with the a/c on for 10 minutes to stabilize the gage. Checking it when it hasn't been on will always show high. If you run it for 10 minutes and it shows good, you have another problem.
I think it goes by pressure? If it says there is enough, tap the AC motor with a hammer, with the ac on, that might do it, somtimes they stick and all you need is a few good taps.
