Comparing the old and updated PDSs, I noticed that the existing ACEA-C5 Castrol Edge Extended-Performance (EP) 0W-20 SP, without reformulation, is apparently also certified for the new ACEA C6, which along with the new ACEA A7/B7, is the strictest ACEA specification, stricter than ACEA A3/B4, ACEA C2, ACEA C3, ACEA C5, etc. It also carries many European-OEM approvals.
I am now thinking that the main difference between stricter OEM approvals and less strict OEM and/or industry approvals is the
antioxidant (AO) content. More antioxidant (AO) results in a longer oil-change interval (OCI) and a cleaner engine among other things. ACEA C6 and the accompanying European-OEM approvals are the strictest approvals in the world. Given the fact that Castrol Edge Extended-Performance (EP) 0W-20 SP also claims a 20,000-mile OCI due to its higher antioxidant (AO) content, it is a win–win.
I still think TGMO 0W-20 SP is also a great choice with its polyol ester (POE; solvent), high moly (AW/EP/FM), and high boron content (dispersant), none of which Castrol has. However, I doubt TGMO 0W-20 SP has a high antioxidant (AO) content like Castrol has.
ACEA-C5 and ACEA-C6 versions of Castrol EP 0W-20 SP are identical:
It is not clear in the PDSs if Castrol is actually referring to the EP gold bottle. I am guessing that this is the case because of the Euro-OEM approvals.
In addition to providing LSPI and timing-chain protection, ACEA C6 reduces the valvetrain wear by 18% with respect to ACEA C5, improves the fuel economy, and reduces the engine and turbocharger deposits.
Oronite OLOA 54720 additive package meets BMW LL17FE+, MB229.71, Volvo RBS0-2AE 0W-20, WSS-M2C947-B1, WSS-M2C962-A1, ACEA C6, and API SP/RC (ILSAC GF-6).
www.oronite.com
The HTFS/VII table lists all the Castrol 0W-20 flavors. The flavors to avoid are Castrol Edge High-Mileage 0W-20 SP and Castrol GTX Full Synthetic 0W-20 SP due to a thin base oil (BO) and a high viscosity-improver (VII) content.
It is theorized that the wear for the following engine components depends on these variables among other things: Bearings: high-temperature, high-shear (HTHS) viscosity, TBN/TAN/base-oil oxidation performance (lead and copper corrosion) Piston rings: base-oil viscosity, TBN/TAN/base-oil...
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