I'll use Pennzoil Ultra or Mobil 1 Extended Performance if that's what's required to get to 5K/5mo or 6K/6mo without concern. What I'm unsure of is if the short-trip acid problem (or whatever) is actually so bad that it kills even a good syn within 3K/3mo.
I know, "Do a used oil analysis..."
I know, "Do a used oil analysis..."
