The oil change interval depends on how much you drive the motorhome. 3-5000 miles is a safe interval for a normal vehicle, 6 months is good for a vehicle that isn't used much.

You didn't say what year the motorhome is, or whether the engine is a 2 valve or 3 valve engine. Recommended oil can be 5w-20 or 5w30. Use Motorcraft or Wix filters. Avoid Fram.

Post the year and we can probably find a downloadable copy of your owners manual for you, or go to this link and download an F-53 motorhome chassis for the proper year.

http://www.motorcraftservice.com/vdi...S-EN&YEAR=2004