1974 VW Karman Ghia with unknown mileage. New friend has over a year on unknown brand 10w-30. Small amount of sludge on plate. So I suggested Shell's Rotella T 10w-30, now avail at Pep Boys, here in So Calif.
'10 Hyundai Elantra
5,000 mile OC
Out : Mobil Super 5000 Conventional 5W20 , Pure One Filter
In : Pennzoil Platinum 5W20 , Pure One Filter
Planned OCI : 6 Months / 6,500 miles (trend is to hit time limit first due to more in - town , stop & go driving habits) .