I’m sure this has been discussed elsewhere, but really tired of 5w30 oils (including Amsoil) dipping from grade, not just to the boundary between it and xw20, but well past (this XL dipping to 8.7ish, well below the true boundary between the grades). I’m not concerned about 0.1 difference, but 8.7 is well below xw30 grade.
Is it a Blackstone, or inadequate oils, or is 8.7 just as good as 9.5?
I’ve been stressing keeping my visc above 10.0, sometimes succeeding, sometimes failing. Amsoil SS didn’t exceed expectations, though wear and TBN, and other detergent & wear components were way better than any OTS Walmart oils. Time to go to a thicker oil (xw40) upfront??? Maybe it’s time for a API xw35 grade, to possibly separate oils that will keep a decent ending visc vs the ones that start low, and go lower, or even start decently, but still dip below to xw20 boundary. I don’t see any OTS 5w30 oil (not even Amsoil) that stayed in grade in challenging DI engines, let alone TDI. Maybe high mileage oils??? Or Euro???
I may be mixing causation with correlation, but I had much better results with Valvoline PB Restore (in the Ecoboost) and Castrol’s Euro 0w30 SL (Belgium…the true German version predated my usage) in a Subaru turbo EJ25. Both stayed above 10.x. Both now hard to get. I’m looking toward trying testing of HPL, but seeing the shearing or diluting issue not totally eliminated with their “low-end” PCMO. But assuming “dilution,” as in the Ecoboost, hard to rationalize an even more expensive HPL as supposedly dilution does not discriminate between high-end oil and mid-tier…though the “resilience” to the dilution might favor the hi quality oils.