For their severe service still? I own a 07 Altima with the QR25DE. It has a 5 quart sump. I rented a Yaris this weekend. It has a 1.5L. I took some time to look at the owners manual. It has a 3.9 quart sump. Toyota calls for 5,000/6 month OCI's. With the rev happy 1.5L. This engine probably puts the oil through a lot of stress. Toyota engineers think this OCI works for this car and most other Toyota's. Why does Nissan still think that their engines with the proper SM rated oil can't go more then 3,750/3 month OCI? Even GM uses their OLM on their Ecotec's. They can go up to 6,000 miles on their 2.2L's. It's been a little over two months since my last OCI. I have put on about 600 miles so far. I only drive 4.2 miles one-way to work, all city. I do get up to 55mph on part of the drive, this is the speed limit on that certain road I travel. I check my dipstick once a week. I have never noticed foam on it. So it looks like I'm buring off the fuel in the oil. I want to try 6 month OCI's. I been using Formula Shell oil. I have a whole garage full of it. You can't beat the price at CSK.