Any deflection more than 3/8” with moderate thumb pressure mid-span on the belts on these cars is too loose. That’s tighter than most people think is necessary or good but it is what is needed and is not too hard on the bearings. On the 3.2/3.5 engines, if the a.c belt is only slightly loose (not enough to slip or squeal), it will make a vibrating noise as the engine is accelerating thru about 2000 rpm.
But as already said, if still squealing with a.c. on and with proper tensioning, your compressor may be failing. The compressor may be low in oil, but if it has never needed charging and still has a charge, it would probably not have lost any oil either, but still could be failing.
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs
Last edited by peva; 07-05-2019 at 06:52 PM.