I had a small/minor oil leak that I fixed after seafoaming my Jeep. At the time when I did seamfoam my engine (160k miles), it didn't make the oil leak any worse or better. So, I guess it's just personal preference. In my honest opinion, my ZJ runs a hell of a lot better since seamfoaming it but ultimately, it is your decision. If it were a major oil leak, then your may want to pass the seamfoaming in the crankcase and just stick to the throttle body/vacuum lines.