Castrol GTX 20w50, good oil (in minerals)?

[twvenezuela]

with 4500Km OCI can i trust my renault to the GTX?

a work friend toll me that this oil "puts black quickly", is thios true?

my usual oils are SL, but plan to use GTX from now, because i can find it almost everywere.

thanks for your inputs

asf

 

[kingrob]

I've used 20w50 Castrol in many of my cars. I've never seen them turn black quickly; FWIW you'll find a lot of people here believe that oil darkening means the oil is doing its job trapping contaminants.