Oil Pump Removal and Replacement

Written by: Mike Ervin

This article is intended to help with removing and replacing your oil pump with the engine still in the truck.  Our trucks have plenty of room to get the pan off without having to raise the engine, so it's not really all that hard.  Let's get started.


First, let's get the truck up on some good jackstands so we will have room to work.  Remove the tranny dust cover if it is an auto so you will have more room at the back bolts on the pan.  Drain the oil from the pan and reinstall the drain bolt.  Now you can start taking out all the pan bolts.  There is twelve 3/8" and four 1/2"  all total.  Two 1/2" bolts at front and two at back, with six 3/8" on each side.  On the passenger side you will have a cooling line clip (if auto tranny) and a battery cable support clamp mounted to two pan bolts that are double headed.  Remove the nut, then the clip and clamp and move the cable and cooling lines over out of the way.  There is also two pan rail stiffeners between the pan and bolts.  Once all the bolts are out, you will probably have to pry the pan loose as the gasket will probably be stuck.  Don't get too crazy because you don't want to warp the pan rail.  After the pan comes loose it's just a matter of dropping it down at the back and slide it out.  Now before anything else, clean all the gasket material and gasket cement off the pan rails on the block.  Clean the pan real good and set it aside.  One part and we have it all removed, the most important part, oil pump.  Now after the pump and oil pump rod are out clean everything up real good.  Rest a little bit and get ready to put it all back together.


One thing I would like to recommend you doing since you have the pan off.  If the engine has few miles on it, why not install a new rear main seal?  You will kick yourself after you get back together and it leaks.

Before installing the oil pump you need to prime it.  Submerge the pickup into a pan of fresh oil.  Turn the oil pump until oil starts coming out of the pump.  Now it is ready to put on the engine.  To install the oil pump you need to put the pump rod into the pump and slide it up onto the main cap.  The pump rod will need to mate with the distributor drive gear so use a light to look up in the hole and find the direction you will need to have the rod so it will line up right.  Tighten the pump bolt to 65 ft. lbs.

Now it's time to put the pan back on.  You will need a pan gasket set.  I highly recommend a Fel-Pro #OS-34510R one piece silicone rubber gasket.  This gasket will fit either side dipstick.  I used this gasket and have no leaks at all.  Anyway, whatever gasket you decide to use it's time to get started.  With the Fel-Pro, it comes with little plastic stickups to help hold the pan and gasket up in place until you get the pan bolts started.  It also comes with new pan bolts because the old ones won't be long enough because the gasket is thicker than stock.  If you are using a set that has two rail gaskets and front and back end seals, you need to glue the pan rails to the pan.  Also on a 4 piece gasket set, use some silicone at where the rail gaskets and rubber end seals meet.  With the Fel-Pro don't use any gasket cement.  Just a little silicone at the place where the ends go up into the block.  The Fel-Pro has metal crush limiters built in to keep you from over tightening and crushing the gasket.  Once you get all the bolts started you can tighten them all evenly.  Reinstall the cooling line clip (if used) and battery cable clamp.  Put the torque converter dust cover back on if a auto tranny.  Reinstall a new oil filter filled with new oil.  Lower the truck and finish filling with the rest of your oil.  Start it up and see if you have oil pressure.  Let it run for a little and check for leaks while running.  If no leaks, and you have oil pressure, pat yourself on the back for a job well done.