We have an '07 Suburban with a 5.3L that has over 260K miles on it. Motor has never been out of the truck. I religiously use Seafoam in the cranckcase about 200 miles before an oil change. We bought the vehicle used with 212K miles. The engine was plugging the oil pressure sensor filter/screen inside the block (common problem with the LS). I replaced the filter/screen and ran 8oz in the crankcase which is more aggressive than Seafoam recommends. After dumping that oil and running it before every oil change like I stated, we've put over 40K miles on the truck without plugging another filter/screen. Oil gets changed every 5,000 miles using Amsoil OE 5W-30. My .02