Red_Bean_Bun
Well-Known Member
Made the switch to German Castrol from Mobil 1.
Was having issues with all all the tapping sound and was look for a replacement for this servicing at the same time.
Read up the UOA results from a number of sources and it seems GC is more shear stable - stays at 12.x cst@100 (operating temperature) and it's thin 72 cst @40 meaning it lubricates well at cold start (and that's when engine damage usually happens). It stayed close to the BMW spec (12.5 cst@100) for 8000km. Mobil 0w40 sheared and dropped to 11.x cst@100 even though it has a higher TBN and HTHS.
The only point of contention is that GC is said to have a very low HTHS (2.9) versus 3.8 for Mobil. But most people recognize that since GC is ACEA A3 - this means it has to be at least 3.5 (comparable to Mobil). And it's the only ACEA A3 verified in that grade. The other key fact to support this is that it is BMW LL-01 certified. Another plus point is that the base stock is group IV PAO while Mobil is group III hydrocracked.
The other thing is that it is not up to the latest API SN rating. But I always think that the more advanced the rating - the less additives it will have and the less emissions it will generate. So with an API SL rating it's loaded with additives. And the additive always goes first before the oil thins so perhaps this is one of the reasons it's more shear stable.
Quite happy with the change to GC. Engine has a quieter cold start and the tapping sound is gone. Being that it's fresh oil which is thicker - the ride is not sluggish. In fact feels better than before. Will revert later on the performance over time.
View attachment 55156
Along the way ordered the rare SAF-XO for my rear differentials. Swapped out the Liqui Moly 75w90 - felt it was thin 14.4cst@100 versus OEM (15.5cst@100) at operating temperature even though both are GL5 certified. In fact if you use the Liqui Moly site to help you select the right oils for your ride - LM recommends their 75w140 oil and not the 75w90 which I think is too thick. SAF-XO is 75w90.
Differentials create a lot of heat and I think going back to OEM would do it some good. Used Liqui moly previously because the SAF-XO was pretty hard to find.
View attachment 55154
I do not work for Castrol.......just like to look at oil stats.
Was having issues with all all the tapping sound and was look for a replacement for this servicing at the same time.
Read up the UOA results from a number of sources and it seems GC is more shear stable - stays at 12.x cst@100 (operating temperature) and it's thin 72 cst @40 meaning it lubricates well at cold start (and that's when engine damage usually happens). It stayed close to the BMW spec (12.5 cst@100) for 8000km. Mobil 0w40 sheared and dropped to 11.x cst@100 even though it has a higher TBN and HTHS.
The only point of contention is that GC is said to have a very low HTHS (2.9) versus 3.8 for Mobil. But most people recognize that since GC is ACEA A3 - this means it has to be at least 3.5 (comparable to Mobil). And it's the only ACEA A3 verified in that grade. The other key fact to support this is that it is BMW LL-01 certified. Another plus point is that the base stock is group IV PAO while Mobil is group III hydrocracked.
The other thing is that it is not up to the latest API SN rating. But I always think that the more advanced the rating - the less additives it will have and the less emissions it will generate. So with an API SL rating it's loaded with additives. And the additive always goes first before the oil thins so perhaps this is one of the reasons it's more shear stable.
Quite happy with the change to GC. Engine has a quieter cold start and the tapping sound is gone. Being that it's fresh oil which is thicker - the ride is not sluggish. In fact feels better than before. Will revert later on the performance over time.
View attachment 55156
Along the way ordered the rare SAF-XO for my rear differentials. Swapped out the Liqui Moly 75w90 - felt it was thin 14.4cst@100 versus OEM (15.5cst@100) at operating temperature even though both are GL5 certified. In fact if you use the Liqui Moly site to help you select the right oils for your ride - LM recommends their 75w140 oil and not the 75w90 which I think is too thick. SAF-XO is 75w90.
Differentials create a lot of heat and I think going back to OEM would do it some good. Used Liqui moly previously because the SAF-XO was pretty hard to find.
View attachment 55154
I do not work for Castrol.......just like to look at oil stats.
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