Contour Enthusiasts Group Archives Forums General Troubleshooting Tapping sound coming from left side of engine

I have a tapping sound coming from the left side of my engine (I have a 1996 Contour SE 2.5L V6 Duratec engine).

I thought that the sound was coming from somewhere around the serpentine belt area, but I had a neighbor (that is always out working on one of his four cars) come over and take a look. He said that he thought that it was a lifter or valve that was stuck because of carbon buildup. He suggested getting an oil additive that would clean the lifters and valves and see if that would do the trick.

Last night, I bought CD-2 oil detergent. I took the car for a drive and then my wife went to the supermarket. This morning I started the car and the sound seems to be gone, but every once in a while it comes back, but much fainter than originally. I plan on buying another bottle of CD-2 oil detergent tonight.

I have the following questions:
- Could this tapping sound damage anything?
- Is this is a common problem?
- Could this be from carbon buildup?
- Could this cause the "check engine" light to come on? If so, how can I reset the check engine light?

Thanks ahead of time for any and all help.

Mechanic wanna-be