Just changed the oil on a 3.0 diesel merc and now the engine rattles under load until the oil/engine is hot. Used fully synthetic 5w40, previously tried 5w30 both recommended the 5w30 was worse.
Both oils spec'ed to MB oil numbers.
Previously car was fine from cold on the old oil, no idea what it was.
Should I just not worry about it given the numbers are to spec ?
Cheers Vin