2007 Envoy 4.2L-6. I always use full synthetic Mobil 1 oil as did the previous owner. My problem is when I check the oil level on the dipstick. After wiping the dipstick clean, I reinsert it then pull back out. The oil level is good on one side, but if I spin it around to the other side, it is perfectly dry. How could that be possible? I get the same results repeatedly. This dipstick is not the flat type but the bullet shaped type and flat on 4 sides. Any reasons why this is happening? Thanks for any replies.