Ok, probably discussed before and I know the marketing hype of PP. My buddy has a 2000 Nissan Frontier pkp with I believe the 6 cyl. He called me today asking about engine pricing. Seems that he has an oil leak and has neglected his OCI a "bit". I said what, 5k, 10k? He doesn't know. I told him (other than an oil change with a high mileage oil) to do nothing until I could get a look at it to see where it's leaking from. So, IF we find the leak and can repair it, and IF he's sludged it up (besides Auto Rx), what can we use to clean it up a bit? Short OCI's with....?