When should use synthetic blend?

[dave1251]

Use it when it meets specs, you use it at the OCI recommended by the OEM, and when its the lowest price option off of the shelf.

 

[DavidJones]

I use Motorcraft semi-syn in my 2.7 Ecoboost. It is cheap. It is readily available at the Walmart 100 yards up the shopping center. It requires no rebate effort. An Amsoil analysis says that fuel dilution was right at the upper limit of acceptable after a 7500 mile oci and no issues otherwise. For me, I see no reason not to use it.