Hard to say. Total system capacity is 25 ozs. If it's so low as to keep the compressor off, you're likely to need at least a pound. But really you should have a dual gage set and use the chart in the FSM (outlet vent air temperature) to know when it's to the proper level.
If it is low, you have lost an unknown quantity of oil - either use 134A with oil in it, or get a separate can of oil and put it in. Total system capacity is 5 oz. If your system is empty, or close to it, of 134, I'd go with 2 to 3 ozs. of oil. If only topping off, 1 or 2 ozs.
Use PAG oil *only*. PAG 46 (ND-8) is what came in ours, but with age and wear on the compressor, wouldn't hurt to go with the slightly thicker PAG 100.
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs
Last edited by peva; 05-20-2011 at 08:23 AM.