Well I am certainly willing to try changing the oil and seeing what happens. I spent a little quality time with the stethoscope and truly there was no discernible difference between the noise at the timing cover versus water pump. I will have to remove some plastic before I am willing to probe a tensioner. Sometimes the diagnosis from a "real mechanic" coupled with my innate belief that each odd sound is either the engine about to blow, or rabies, blinds me to the basic steps in troubleshooting. I will definitely keep you posted.