I have a high mileage Civic (close to 200k). I changed over to Mobil 1 from a pure dino diet from new. Ever since about 120k for the first few minutes of running there was a clattery sound under the hood at 2500RPM+ and under 35F. I know people have reported the opposite with Mobil 1 but in my case 20F this morning and no noise even at startup and up to 3000RPM on a stone cold motor. Maybe its filter helping, which btw is a Fram installed by Walmart Lube Express unknowing to me until I peeked under and saw orange.