Originally Posted by ka9mnx
Originally Posted by JeffKeryk
Since it's cheap, I would run ST Synthetic HM 5w30 or 10w30.
Agree. Sounds like this engine hasn't had a good oil changing life. This would be my recommendation.
It certainly hasn't.
It was my father's girlfriend's car, he said she used Formula Shell 10W40 forever, but I think she probably didn't change the oil for the last 4-5 years she owned the car, and really really abused it, carrying gravel in the back seats and stuff like that.
This is after 1500 miles of Supertech.
I'm actually really leaning on Maxlife, though, mainly because it seems neat, and worth the extra $3. The other reason, too, if I get 5W30 Max Life, I could actually streamline my oil for all our cars in the household, since my mom's Five Hundred is spec'd for Motorcraft synthetic blend 5W20, but I've found it runs better with 5W30 Motorcraft synthetic blend. So since my car will take 3.5 quarts, her car takes 6, the leftover quarts can go into her car and vice versa. I also feel a little partiality to Valvoline, in the past with my mother's Taurus, I loved the way it ran on Valvoline full synthetics, I liked them even better than Mobil 1.
One reason I'm thinking my mpg stuff is oil related, is that I feel a definite difference in engine smoothness/pep when warm, and the engine just revs more freely. I'll also be switching to another oil filter with a bypass, as the stock Nissan filters have no bypass, but I have leftover filters from my old Jetta that are 3/4 threaded and have a bypass (they're set relatively high, I think 15 PSI?) I was also thinking of a 1068, as I used those on Toyotas in the past with great luck, and have one 1068. But the 1068 probably will up it to 4 quarts total, as it's such a big filter.