I had my car on a lift today and We noticed some oil underneath the plastic cover under the bumper, looked up top and it looks like the OCV on passenger side is leaking, lost about a quart (the last time I checked the dipstick was about 2 months ago) no cel nothing, so my question is can I just replace the o-ring in the OCV or should i just replace the whole part? was that a lot of oil to lose over 2 months? (a quart) Lexus did my seals and timing belt 3 years ago btw... Blahhhhhhhh

Are you sure its leaking from there? Since you mentioned that you had the timing belt and seals replaced before, it's possible that it might be leaking from the vvti gear. Or maybe the previous mechanic didnt do it correctly for the cam seals and cam cover. Im assuming you have the gs400?

Yes it's a 400, theirs oil leaking out the OCV looks minor. Would I be covered if they didn't do it right? I doubt it, I have to check the oil filter also

If your sure its leaking from there, you could just replace the o-ring if lexus sells them.