Just changed me oil on my car as it needed topping up and I was not sure what oil it had in since buying it. Used a sti pink filter new sump washer and castrol edge sport 10-60 as I can get it quite cheap and a few people seem to recommend it. Did everything according to what I read cranked it over with cam sensor off before starting and made sure it was up to the second little circle at full. It was dead slient before but now seems to be a bit more noisey and after a good run now seems to be a slight clunk knock on tick over. Not sure quite where it is coming from but seems most from the left side possibley. just hoping it's not the bottom end going. It's a 1997 wrx type ra and has only just turned 30K miles with full jap service history and has been very well looked after by the condition of it.

 

i had a simuler experience when chnaging the oil on my low mileage import. the engine sounded awful. I just ran it for a few hundred miles and its quiet now. Could just be the fresh oil, is a bit thinner and the engine sounds louder.

 

Could be piston slap, mine developed it after a oil change too, it comes and goes when it feels like it worse when cold though