What is this noise? bearing or lifters?

[john90290]

2002 Boxster, 97k, one previous owner, dealer maintained.
http://www.youtube.com/watch?v=ymHjSS1cCqA

Please note that on the video it sounds much deeper than in real life. It's for sure right side. I've changed the spark plugs as I read that this sound can be caused by loose plugs...no change.

I changed the belt, ran the car for a few seconds with no belt, sound is the same.

This sound started to happen once and a while after I returned from work and now it's all the time.

I don't run the car often as I have a car issued to me at work so it runs weekends and sometimes during the week, I baby the car until it gets up to operating temperature (<3k) and then drive it as intended.

I live in San Diego so I has not been below 45 in her life, the car grew up in San Francisco.

I just changed the oil and now plan to change it again to tear apart the filter inspect for detritus of my main bearing and see if fresh oil might loosen the lifter if indeed it is a lifter...


Any thoughts? Why so prominent on the right side? If it is the main bearing would it make a sound when warm and then none when hot?