I'd love to hear any ideas from the group on this one. 2002 Ford Escape XLS, 2wd, 3.0l V6. I believe this is a Duratech 30-RFF engine. My wife came into the house and said her car was making a noise. Went out to listen...what a nice tapping noise the vehicle is making! I shut it off and after a few minutes pulled out the dipstick, which showed NO indication of oil. Looked at the little sticker in the window to see when the last oil change was done (I never drive the vehicle, but still my fault for not making sure she was having oil changes done [:@]) and it was 18k miles overdue. Added 3 quarts, which made no difference in the sound. Thinking that maybe she gummed up the engine by running it so low, I added a half pint of Sea Foam. Drove the vehicle for a while and then took it for an oil change. No difference, still have the tapping noise.

Here's what I know. Doesn't make the sound when the engine is cold, only when warm. Most noticeable between 1k-2k rpm and when letting off the accelerator. No check engine light or noticeable difference in engine performance. Seems to be coming from the top of the engine. Frequency increases with rpm's...the higher the rpm's the more rapid the tapping sound.It sounds like what I would describe as valve tapping, but why would it only be when the engine is warm?

ANY ideas are greatly appreciated, as I need to narrow the possibilities before deciding to tear into the engine.