GMC Repair: rattle when accelerating, buick riviera, belt tensioner

Question
I HAVE A 1990 BUICK RIVIERA AND THEIR IS A RATTLE UNDER THE HOOD THAT SOUNDS LIKE THE WATER PUMP GOING OUT BUT IT ISN'T.  WHAT REPAIR IS POSSIBLY NECCESSARY...

Answer
Hi
I would check the belt tensioner and also any idler pulley on this motor.
You could also take the belt off, and see if it still makes noise.
If Not, you have a belt driven accessory problem.
If noise continues, You MAY have an internal engine problem, and should then go have it checked out.
I Hope this helps.
JUST ADVICE from experience.
Good Luck
Pawl