Hey Fat Boy (your moniker not mine!)
I believe far more important then brand of oil (Valvoline, Castrol) and type of oil (Synthetic, regular, or blended) and even weight of oil (15W50, 10W40, 5W40) is regular changing of oil and filter.
I think for most of our cars the rules don't apply since they don't get the use that was intended at the time of sale. If you store your cars in winter, and then put 2,500 miles a year on your car "in season", for certain you need a fresh oil change and filter at the beginning of each season. If you do more than that, say 5K mile a year, then you'll need the same with an interim change.
If your car is a daily driver and you put 12,000 miles a year on it, and use it in the winter, then the "W" designation comes into play as does more frequent oil changes.
After listening to a Mobil 1 presentation last year at Starfest I had to believe what they are saying about synthetic versus standard. I have used it since then. Others seem to think they develop additional leaks more frequently when they switched to Mobil 1, but I have not. My mechanic doesn't believe it either. A leak is caused by a weakness or failure of a gasket or seal. If your gaskets/seals are in good condition, they'll hold. I have no leaks, my undercarriage is as dry as a bone in the desert.
VERY IMPORTANT: if you have not heard Joe A's presentations on oil changes, you may not be aware of this little rubber seal found at the top of the filter housing mounting base. More often then not, these seals are LEFT OUT since many don't know about them. If the seal is left out, you are not filtering oil. I can't tell you how many members of this group have discovered this, but it is quite a few and I'm among them.
Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored
