This will happen quite frequently (I hesitate only slightly from using always) when switching from dyno to synthetic on medium to high mileage vehicles. This is because synthetic has smaller molecules which will find and penetrate smaller cracks than dyno. There's a high chance you can stop the leak by switching back to dyno, or using autorx at
http://autorx.com. See
http://bobistheoilguy.com for any questions you ever had on oil, lubrication, filters, and additives.
