I am new to this forum.
I drive a 2004 Jeep GC 2.7 with the Mercedes OM647 fitted.
The dealer used Shell Helix Ultra 5W-30AB but this oil is not available in South Africa anymore.
The vehicle has completed 100,000 kms (60,000 miles).
Will I be safe to move to Shell Helix Ultra 5W-40 or even...