I would think that if Honda had a piston slap issue, after only 30,000 km, nobody would be buying them. Why buy an overpriced import with piston slap, when you can get a cheaper domestic with piston slap? Yes, they are known to have noisy valvetrains & injectors, but I've never heard of any Honda having a piston slap issue (well, maybe the old B20 Prelude motor). Either way, it sounds like Robert M. has more of a mechanical problem than an oil problem.