You might find a downloadable version in the Altima section here at the forums or do a Google search for it. As far as your grandpa, as long as he's not using the gauges he's had from the 60's, he'll be fine! R-134a didn't get introduced until 1993 (for Nissan, 1994) and uses differant type fittings than the R-12 systems did. If your AC is blowing cold, then there is really no need to check anything other than your cabin filter every 15000 miles (located behind the glove box). Freon in a sealed system will not have to be serviced unless a leak developes. If it was leaking, the system would blow warm. If your AC blows cold, leave it alone!