Pulled the valve cover off my 91 Honda CRX Si today to get a visual of the timing belt. I was very pleased to see that things are nice and clean under the cover. Engine is a D16A6 with 32,300kms. I've used many different oils in the engine: Castrol Syntec 0W30, 5W30, 5W50, Motomaster Full Synth 5&10W30, Pennzoil Pennzane 5W50 and now it's full of Pennzoil Platinum 10W30.