I purchased my Jeep Patriot new 3 months ago. It's a 2010 and has the 2.4 (4 cyl) engine mated to a 5 speed. I changed over to synthetic (Penzoil Platnium)at 1800 miles and today I checked the oil and was a 1/2 qt low. I now have 4600 miles, is it normal to lose 1/2 qt within 2800 miles? The first 1800 miles it didn't lose a drop on the factory fill. Could it also be the synthetic oil? Thanks