[C320-list] Mixing Oil Brands

[Bruce Hunter]

We just bought a 2000 Catalina (Hull 719) in Seprember. Sadly the time has wizzed by and we'll be pulling her for dry storage on November 16th. Tomorrow we will be bringing her down from Baltimore where we hid her from the storm (Protected floating docks are GREAT!) and the engine will be nice and hot. I want to change the oil but I don't know what the previous owner used. I am planning on using Shell Rottella 15W-40 since I use it in my truck diesel and I've read it works well in the 3GM30F as well. I know I won't be able to get all the old oil out and some will be left in the pan, I'm thinking I will change it tomorrow and then once more before pulling it to lessen any reaction of different oil brand chemical packages negatively reacting with one another. Any thoughts?
 
Bruce
Hull #719