Well I'm thinking of doing my first o/c on the Ranch and have been contemplating using Mobil 1 full synthetic. The previous owner used regular 5-30 Quaker State oil since new.. I have read good things about Mobil 1 and was wondering if I should use the 5-30 or the 0-40 (I think it is)? I was reading on the 0-40 bottle the other day that it is very compatible with Ford 5-20 oil but I am wondering if it would be too thin? Most guys seem to be using the 5-30....Any suggestions?

 

Living where you do and having all the changes in the temperature I would stick with the 5-30.

 

If it does not use oil and does not leak, I would keep using the same oil. I would not have started with Quaker State, but if that was what was used, I would not change.