I have a small stash of 5W-20 PP from a previous auto and would like an opinion on using it up my 2000 Ford Ranger (only 46K) mixed with PP 5W-30 approx half and half? Will that make it too thin for the 4.0 engine? The vehicle is now my main transportation but still doesn't get a lot of miles put on it as I ride the Can Am a lot. Motor seems in excellent cond, uses no oil. I should note that the truck sat for many years with only 1,000 miles or so per year but the oil was changed yearly using dino. Now that I have begun using it more, I'm thinking of going with synthetic. The oil was recently changed with Mobil 5000 & MC filter so its won't need changing till spring.