Is GF-4 Castrol GTX a blend?

[ARH_0700]

Does anyone know if the new GF-4/SM GTX is a blend? Not the start-up, just the regular GTX.

 

[DSteven]

I purchased 5qts of the GTX 5w30 SM/GF-4. I was pleasantly surprised at the flow compared to Mobil 1, when I placed a quart of each in the freezer for a few days. Anyway, I am hoping it is a blend. I've read where the previous GTX was great, except in low temps.

 

[drive it forever]

Supposivly, any 5w30 that is rated the new GF-4 are a part synthetic blend (from what i here on this board). If that is true, companies like castrol dont want you to know that and would like you to buy the semi synthetic blend anyways.