Mr. Benzadmiral, I am really enjoying my ownership of the year newer '17 Lacrosse, with 2 extra cam drive chains, center cylinders deactivation, auto stop, continuous cam phasing, variable-tuning intake runners and 8 speed Aisin Warner fwd transmission. So far it's been a problem-free luxury starship, that's as docile or ferocious as I choose to drive it, while still averaging 29 mpg (80% interstate). I've had it 37k miles/ 3 years + 1 month since brand new and if it (hopefully) has a slow, delayed decline in its life, I plan to keep it for some time to come.
I questioned whether all Dexos 1 Gen 2 5W30 oils are the same, and came to the conclusion that they are not. I selected Motul Eco Lite D1G2 for its higher HTHS (3.3 cSt), (supposedly) more ester content, and increased use of salicylate detergents & AW package. I buy it by the case for about $40 each for 5 liter jugs. On paper I would place Ravenol as the best, as its base stocks are likely the most oxidation resistant, and its additive package brings B & W into the mix. I'd think Amsoil SS 5W30 or Red Line Performance 5W30 would likely fit in with Ravenol's pluses, except the add packs don't have the W (value?). Total (Quartz 9k?) is also a serious contender among the best as would be Schaeffer's. And if you'd rather obtain more available oil, then there's some money savings to be had with Pennzoil Platinum, M1 EP, Castrol Edge EP, Valvoline Advanced, Kendall GT-1, QS Ultimate, Red Line D1G2, RP, etc... Or if you're wanting more cleaning, less soot, less oxidation, the Lubrizol spider says the oils rated for MB 229.51 and 229.52 combined with a steady diet of ultra low sulphur top tier gas might be a good alternative.
We could make some mention of Noack volatility numbers, but you'd see my hierarchy and those test results are already aligned.
Dexos 2 is made to prevent negative reactions with a diesel particulate filter, and while it does have an elevated HTHS of 3.5 - 3.7, unless you're getting racy with yours for moderate periods of time, it's really a Venn diagram overlapping intersection with MB 229.51, and likely will just cost you a little gas mileage for increased cleanliness and slightly longer OCIs.
What kind of mileage is your OLM predicting for an OCI? Mine seems to be set at a constant 7500 miles, but like I said mostly highway miles, and never short-tripped, and I'm just gradually increasing to ~ 6k miles actual OCI, which is as much as I'm willing to risk with reports of chain/ tensioner issues in earlier model years of the 3.6 DI DOHC.
Also a thought - yours has the 6 speed auto - with 45k on the clock it's important to get the Dexron VI exchanged from that unit soon if you haven't already. I thought I had seen numerous complaints from drivers with V6 Impalas stating their transmissions started having problems just before 100k, but many if not all thought the ATF was a "lifetime" fluid that would give the transmission 200k+ miles of trouble free operation. Didn't turn out that way.
Anyways, cheers from the river city.
