As long as you'll be using R12, you can charge until the sight glass clears. But keep an eye on the pressures. Your high side "should" run around 2.2 to 2.5 times ambient temp. The clutch fan will have a lot to do with the pressures, so make sure it's operating properly. Also, both fans should be running. Once the sight glass clears, add an ounce or two more, but don't overfill it..Make sure you purge the air out of the lines before adding also..No need for a fan blowing into the grille. You don't drive that way...:) But check your pressures at a fast idle..Just watch the sight glass and pressures for anything unusual....Hope this helps..

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