dougrainer wrote:
35 years ago when Mobil 1 first came out, we had a Mobil engineer that purchased a Motorhome from us. I asked about the NEW at that time syn oil. He stated that you never install Synthetic oil in a engine that has already been broken in. He said that the Synthetic oil will leak thru extremely small cracks and voids in seals that normal oil would not. He laughed and said, install it and you will then have leaks you never knew you had. Doug
BS. I've switched a lot of used engines to Mobil 1 over the years without ever having a problem. That includes a couple of IH Scouts with over 70,000 miles at the time I bought them, a used riding lawn mower, a 1993 Ford Thunderbird, a 1991 Ford PU, my used MH (32,000 miles) and its genset. Never had an issue with any of them.
A 10w oil is a 10w oil whether synthetic or dino.