D.J.,
If you have already switched to a multi-grade detergent oil, at your next oil change you might want to try 20W50 oil. Simply stated, the 20 is the "cold" weight and the second number is the driving temperature weight. The higher driving weight usually increases oil pressure. Some people do not recommend changing from single grade non-detergent oil (10 to 30 weight was commonly used years ago, depending on the time of the year) to detergent oil and/or multi-grade oil, unless the oil pan is cleaned and/or after a rebuild.
Supposedly, the non-detergent oil allows particulates to deposit/settle-out in the pan, while detergent oil holds particulates in suspension (to be more easily filtered).
Tim
