Originally Posted By: CATERHAM
First off I presume it's a the older SL/SM formulation which is really a 40wt oil, certainly heavier than M1 SM 0W-40.
I presume the MaxLife you have is their 5W-30?
So there really isn't any benefit to mixing in some RL, you don't need a heavier oil or the higher ZDDP really. But if it was just to use it up I'd add a maximum of one quart of RL to the MaxLife.
Once the MaxLife is gone and you need to get more oil I'd suggest picking up some TGMO 0W-20, it's only $5.65/L, and go with a 50/50 mix with RL. This will give you an appropriately light 5W-30 with a 188 VI, 900 ppm of ZDDP and 350 ppm of moly.
Yes it is the sl/sm formulation, i picked this up for 6 bucks a quart, the maxlife is 5w30