17 Porsche Cayenne 3.6 VR6
~5800mi OCI, 83345mi
Out: HPL Euro 5w30, STP S11242
In: HPL Euro 5w30, Mahle OX983DECO
I wanted to run this oil for a year and test. However, oil consumption wasn't great as I topped up 3qts during this run + 1qt for the filter change (
https://bobistheoilguy.com/forums/threads/mid-oci-filter-change-w-hpl-oil.390860/). After the filter change it consumed about 1qt/1k mi, and I wanted to try to solve the consumption. Also oil was already visibly more dirty that I was accustomed to seeing - HPL doing its thing, no doubt.
I didn't need to drive this car last week so did a piston soak from Sunday - Wednesday. Drained the oil into a clean container first to keep the B12 out of it. There was a lot of carbon on the pistons, but 2-6 allowed the B12 to pass through indicating the rings were clear. Through the whole time period B12 stayed on top of piston #1, I vacuumed the first try out and replaced with fresh solvent. In total, went through 3 cans of B12 giving each cylinder a couple 100mL doses - then dumped what went into the oil pan and let any residual evaporate overnight. Old oil went back in to clean out the piston soak remnants and took it for a 30min highway drive. The following day I added a couple ounces of B12 to cylinder #1 and it drained passed the rings in minutes, piston top was very clean too. Warmed the engine up after that and changed the oil + filter.
It's running great, not significantly different from before, but will continue to monitor the oil level. I'm not sure the HPL would have freed the compression rings on cylinder #1 if that was the problem at hand, so glad I tried the top-down approach.
Note: when examining the STP cartridge the filter media ripped by hand without much effort.
