I was on the Amsoil website looking up a torque spec and they recommended 5w20 for my 98 Expedition.
They said
"Viscosities:
All TEMPS....5W-20 This specification has been updated from 5w30 to 5W-20 per a Technical Service Bulletin from the manufacturer 5W-20 is the preferred viscosity. "
What would be the reason for a TSB for the lighter weight oil.
In a previous thread about Mobil 1 oil differences, the general concensus was a heavier oil (10w30)
They said
"Viscosities:
All TEMPS....5W-20 This specification has been updated from 5w30 to 5W-20 per a Technical Service Bulletin from the manufacturer 5W-20 is the preferred viscosity. "
What would be the reason for a TSB for the lighter weight oil.
In a previous thread about Mobil 1 oil differences, the general concensus was a heavier oil (10w30)