on my 95 Riv, If you remove the cover from the engine, and then If you look straight down just in front of the super-charger neck there is what appears to be a 1/2" OD screw. on mine there is a hex (allen) style bolt. Its hidden but there.
Before you go nuts, Check your tensioner pulleys, one of mine vibrates and it makes a funny sound in drive/Idle. I doubt your oil is low, but if it is, check the service manual for your car, and see what oil it recommends. For the 95 Riv I believe it takes a synthetic...
John