Achtung ! You will be making a very costly mistake using Mobil 1 or any other synthetic motor oil in your W113 SL. I was just recently reminded the reason or reasons for not using synthetic oil in cars our age and will try to recall who, or from where I read, saw or heard the experts remind me.
Shell Rotella, Valvoline, Kendall, and, of course, Mobil branded non-synthetic oils with either a 10W30 (wintertime) or 15W40 (Spring, summer, and early fall) viscosity rating have been my car's engine lubricant for its entire life. You see, my car was passed to me from my German-American grandmother who bought the car brand new and took direct delivery of it at the Stuttgart factory in July of 1966. And, so, I know (having all service, maintenance and repair records since then), exactly what has been used and when it has been used in its forty year life, and the engine has never needed any major repair, it starts and runs whenever attempted no matter the season, has plenty of miles ( and expect it to go one or two hundred thousand more - grandpa drove his 220D over 400,000), and just this past weekend I drove it 370 miles with the engine happiest at 4300 RPM (approx. 80 MPH) and didn't notice any difference on the dipstick level when I returned it to its stable. I.E., MB isn't kidding when they claim that our cars are "Engineered like no other cars in the world !"
Pagoda Lilly