Well, I got a reply from Castrol.
Website still doesn't show anything but GTX, but they verified that the Edge and Magnetek products will work, which gives me options.
Their Reply:
Thank you for contacting Castrol North America.
We regret you experienced technical difficulties, and apologize for any inconvenience this may have caused. Your comments/ suggestions have been forwarded to our web webmaster.
The correct grade of oil to use will be listed in the automobile owner’s manual. As far as whether to use a conventional or synthetic - that depends on the driver, the conditions and the type of driving that you do. Both conventional and synthetic oils will protect your engine – synthetic oils provide superior protection to conventional oils. Synthetics also provide much better protection at extreme temperatures and severe driving conditions. Some automobiles do require synthetic oils – this would also be mentioned in the owner’s manual.
The Castrol US web page (
http://www.castrol.com/en_us/united-states.html) provides information on what oil to use for your vehicle, based on your location, vehicle and driving conditions. On the Castrol home page, click on “Oil Selector” and answer the questions to determine the proper oil for your vehicle.
According to Castrol’s lubrication guide recommended for the 2004 Ford Explorer 4.0 V6:
For All Temperature Ranges a 5W-30 oil meeting Ford Spec. WSS-M2C946-A is recommended
The Following oils meet this specification and are suitable for your application:
-GTX 5W-30
-GTX Magnatec 5W-30
-EDGE 5W-30
-EDGE Extended Performance 5W-30
-EDGE High Mileage 5W-30
Thank you again for contacting Castrol, we value your patronage!
Castrol Consumer Relations