Engine oil Castrol or OEM Mazda

been using Castrol edge 5w-30 for the past 5 years My WRX engine still feels responsive but i know 5-40w is good overhead for high temps

But the Castrol Syn was good too.

I've used Castrol GTX in my E30 for a decade now.

E39 S62 (M5) engine - used both castrol 10W60 and Liqui Moly 10W60.

Just updating! I used to put Castrol Magnatec 5w40 on that Golf, and the engine just improved from day one. Much smoother and with greater response to throttle, and the engine start got like 2 seconds faster, almost instantaneous.

I use castrol edge advanced full synthetic on mine works fine I change it every 6.5K on my 21 5.0

My oil cap says Castrol only, which is what my husband uses. We change the oil every 5000 miles using Castrol full synthetic.

I used to use Mobile1 in my vehicles but switched to castrol edge only becuase mobile1 didn't have very good flow rates at startup in colder climates (like Michigan) as castrol had. Plus it's recommend for asian vehicles and I drive Nissan and Mazda.

Castrol Edge Extended Performance 0W-20. Haven’t had to change the oil yet but I will around 7500 miles for peace of mind.

And one thing I would definitely do is get the Castrol out of there if you intend to keep the car long-term. The recent changes to the oil we are delivered at the dealer is crazy!!! It's not the same as it used to be and I can tell a huge difference in my cars. Have had excess oil consumption, lower MPG and quicker deterioration of the oil over last 6 months using Castrol(and I work at dealer)