GC 0w30

[dlundblad]

Assuming the "cold flow" properties of Castrol 0w30 and 0w40 are nearly identical, is there any reason to buy 0w30 when 0w40 is so readily available? I believe both oils meet the same certifications, both are A3/ B3 etc.

 

[Jetronic]

possibly less VII in the 0W30, and a very slight fuel economy increase.

 

[edyvw]

Originally Posted By: Jetronic
possibly less VII in the 0W30, and a very slight fuel economy increase.

I used exhaustively 0W30, never seen difference in gas consumption between M1 0W40 or Castrol 0W40 and 0W30. However, I did notice that with both Castrols, 0W30 and 0W40 turbo spools faster then with M1. cst of 0W30 is 12.1, and cst of Castrol 0W40 is 12.85. M1 is 13.5, so I think that is the reason.