Having an old or damaged rear main seal (RMS) can cause puddles of oil underneath the vehicle. If oil is leaking from the bell housing area behind the oil pan while the engine is running, then your rear main seal will likely need to be replaced. It is best that all valve covers are checked for leaks before removing the RMS to eliminate other causes. If you are sure that your RMS needs to be replaced, it is still a good idea to check valve covers and fix any leaks being proceeding on to the RMS.
Disconnect the battery and the starter cable. Remove the starter by unscrewing the two starter bolts. Support the engine with crank pulleys from the front and the rear at the flat spot of the bell housing by using a floor jack.
Remove the cross bar under the oil pan that runs from one motor mount to the other. Mark which way the bar goes for future reference.
Remove the clip on the top of the passenger motor mount that holds the fuel line down. Remove the three remainng motor mount-to-frame bolts on the passenger side. Remove the three motor mount-to-motor bolts.
Remove all of the oil pan bolts. Use a screwdriver to gently pry around the pan until it comes off the block. Drain the motor oil, remove the oil filter, and clean the pan and block mating surface.
Look under the motor for the seven main bearing caps with two big bolts holding them to the crank. Locate the rear main bearing cap, which is the last one toward the back.
Remove the rear main bearing cap using the correct size socket. Tap the cap loose with a rubber mallet. Take off the oil pan gasket and the bottom half of the RMS that is held by the rear main cap, and then remove all of the other remaining bearing bolts.
Look into where the rear main cap was taken off, and remove the other side of the RMS. Remove the rear main seal with a pair of pliers (it will be coming out of the place that you dislodged the RMS).
