1997 Oldsmobile Achieva 4 cyl Front Wheel Drive Automatic 85000 miles
Rattling or knocking noise from under the hood at low speed. Goes away gradually as engine speed increases. At 20-30 mph and above the noise is gone completely. Noise started after I replaced the water pump, which means that I had to remove the timing chain to get to it. Not sure I got the timing chain reinstalled correctly. Car runs normally otherwise. No loss of power or acceleration. Tensioner problem perhaps?
It could be a tensioner or? So what I would do is either use an automotive stethiscope or long screwdriver that I could put up to my ear and use the other end to touch the engine and see where the noise is the loudest. Once we know where the noise is coming from then you can figure out where you need to go to find the problem.