Hi all at GM Form. Iam new to your forum.Hope I find everyone well and happy.I have a 1998 Buick Lesabre 3800 engine with 100000 miles.At 50000 miles the sounded like a engine knock only at idle road speed no knock,stop at a red light it would knock, race motor up no knock,take engine supertene belt off no knock drove it 50000 miles that way knocking.Dealer replaced belt tensioner idler pulley, power steering pump,ac compressor,water pump,finally pulled oil pan said motto is no good (bearings no good).all this time I've been all under the car .I keep looking at the harmonic balancer.Is that possible.is that'* what'* knocking

If the knocking goes away when the serpentine belt is removed, and all the accessories have been replaced, then it'* possible you have a bad harmonic balancer.