Well if you go by oil leaks on Land Rovers its 20,000 miles.
If you go by everyone else its 75,000 miles.

 

I think it is safe to say that 100,000 would be a safe number.

 

Just reporting back. It's been about two weeks and 1000 miles after going with Mobil1 hi-mileage fully synthetic, 10W-40. I would say that the engine sounds smoother. It likes the juice.

As far as the leak, I don't notice much difference. Good news is that it doesn't leak more; but whatever the formulation contained in the high mileage formula doesn't seem to slow the leak, either.

In any case, the car is happier now, and I'm certain it will be happier come winter in sub freezing temp with Synthetic.

 

I think that 5w30 or 5w40 would a better choice for winter, rather than 10w40.

 

True, but I couldn't find 5W-40 High Milage oil. Besides, in the Sierra nevada mountains, "cold" is about 20 degrees F. I know people up north laugh at us when we complain of cold....