Engine oil Castrol or VALVOLINE

I run 10w-40 castrol gtx been running it for the past 5 years I drive a 2011 wrx

ran Castrol 20w50 GTX in my 2.4 Naps Z D21 since new the mechanic who put on new head gasket w/215.000 due to a bad radiator said engine looked brand new inside

Used 5w40 castrol for most its life, but vw504 standard is good too. Using it now and the old man says it runs good.

I used to use Rotella T4 as recommended by many on the forums. It was fine but I switched to Valvoline 20w50 because it has the additional Zinc like the Rotella T4, and a bit better film strength which protects bearings at high RPM.

My Mazda3 which I service myself now, Castrol edge 5w-30 and feels happier. Same engine too.

I’ve had good luck running Valvoline VR-1 in engines with flat tappet cams.

Valvoline VR1 in whatever viscosity is suitable for the season and the VR1 has plenty of zinc for old engines.

I always used blue "german" coolant in my e90 bmw oddly it also recommended Castrol oil. Specifically called for it in oil cap

I personally have used the RN17FE 0W-20 (Renault branded Castrol GTX bottles) for 10k km after the innitial oil that was filled in the factory (I don’t know which one was filled in factory). I haven’t noticed any better fuel economy but that can be tough to determine because I drove the car mainly through the winter and did more shorter trips than the original factory first fill oil that I drove with during spring and summer.

Avoid. Tried it, it burnt off very quickly. Back to Castrol with my tail between my legs.