I needed to replace two of my Continentals today, and their website listed my local NTB as my local dealer of these tires. While I was there I was offered a full synth oil change for $59; I asked if they have someone who works on MBs, and if they had 5W40. They said 'yes' to both (well, of course they did), and I agreed to the oil change. After 2 1/2 hours there, they finally completed the work,and I drove off, a bit later for work than I had planned. While I was driving away I looked at the receipt and saw that they had used 10W30 instead of 5W40. Being already late for work, I did not turn around and go back to the NTB. Here is my question: should I get the 10W30 removed and replaced with the 5W40, or should I drive with it in there until the next change? I live in PA with current daytime temps in the low 60s, and nighttime temps in the low 40s.