Have a very slow oil loss which is originating somewhere near the rear of the I6 from below. No indication above. My oil pan plastic shroud cover is lightly coated to the backside with a couple of droplets forming. I thoroughly degreased shroud at last oil change. Don't have a lift so it's difficult to zero in on. My oil pan nut is tight and I change the oil myself. Is there a rear main bearing seal that could slow leak, and if so is it a reasonable cost fix if I can't DIY. I'm at 182K. Thanks.