slight squeek from engine + loose serp belt, 4.0L

98 4.0L
135k, looks like WP may have been replaced before. looks like fairely new gasket
ok over the past 6 months the serp belt has been squeeling bad if i cut the AC on when the engine is cold. I replaced the idler pully on the drivers side and the belt and it worked pretty good for a while. but i have to keep tightening it more every other month. am i just not making it ight enough the first time (i make it pretty tight, less than 1/2" deflection pulling on the belt between ps pump and water pump

just recently i have been hearing a faint chirp (like a pully starting to go out) at highway speeds

question is can the water pump be going out (NO leakage visiible out of the wp weep hole, and cooling is great) or the PS pump going out? (NO PS whine or leakage from pump)

are the $40 cardone (non reman) or AC delco pumps good? and do i need to remove anything besides the belt and fans to replace the pump.

Sounds like you tighten to up the belt a little bit more to me.

I chased one of those squeeks for quite a while just to find out it was the harmonic ballencer. The vulcanized rubber connecting the inner and outer peices was cracked and sticking out about 1/16 to 1/8.