i changed my oil filter today to the usual PCX and i found an indent on the filter. its on the round part of the filter, about 1cm x 2cm across the body. using the picture as an example, this is where the indent is. is it still ok to use? should i change it?

 

It's fine. As long as there are no holes you're good to go.

 

While it is *probably* fine, I would not use it on my car. What if the fliter becomes defective internally and causes a rise in oil pressure? It's not worth gambling a $5k motor for a 5$ part IMHO.