....Andy, it all depends on just how bad it is under there. A good pressure washing most likely will do it....... As for steam cleaning I rarely see that done anymore. We don't have the dirt roads like my earlier days and engines ect just do not leak oil and everything getting gummed up. Still, I believe you can still rent steam cleaners...if so needed.
But yes, if using POR15 that should be good enough prep.
