I've heard so many differences of opinion on what oil to use now i'm bit confused. Im currently running my saff in after a rebuild on 10w40 mineral, as i was told to use a mineral oil for running in, it seems to be alot thinner than i thought it would be and i have a leak comming from the back of the engine somewhere, i don't know if its because the oil is thin and find its way out, but i thought it was the rear main, took the box out and it looked abit damp so changed it, box back in and its still fookin leaking!! but i don't think its the sump as i used a new gasket and silicone...

i always used to use 5w40 fully before as again thats what autodata recommends, but now im not so sure what to use once its run in...??