Hi,
We have a car that consumes some oil at the rate of ~1Qt/1500 miles. It fits the mileage of high mileage at 155k miles on odometer. Is Pennzoil or Castrol "High Mileage" 5W30 oil (recommended grade) a blend with many additives? Any recommendations for these types of oils? She does not check dipstick. She also likes 4k-5k oil change intervals hence the question about blend. Manual states 3750 miles for severe interval.
thanks for any insight