How to Change an Oil Pump on a Car

This isn't specific to jeep 4cyl. because the request didn't specify year, and jeep has used AMC and Chrysler engines. This should be a good general description of how to do it on about any car.

Instructions

1

Set up in a clean area, you will be exposing the internal components of your engine, not recommended outdoors. Dirt and oil make for a cashiered motor. Find what wrench/socket sizes you need and have them close by ahead of time. Saves on trips to the tool box from under the jeep. hint: the two bolts at the back of the oil pan are almost always bigger than the rest, because of the main seal.

2

Secure the vehicle on EVEN ground, preferably indoors. Place in Park, set the parking brake, and scotch the rear wheels. Use the jack to lift one side of the truck until you can place a jack stand under the AXEL. It can slip off the frame and crush you. A friend of mine died under a vehicle, and it was no fun. Repeat on other side. Once the stands are in place you can "walk" the truck higher with the jack and stands if you need more room. DO NOT exceed the height of the jack stands with blocks. Once again dead is no fun. Again if your jeep is "lifted" you might not even need the jacks and stands

3

Now you're ready to drain the oil into a drain pan. Pull the big plug at the rear bottom of the pan. Dispose of the oil properly at a city approved dump bin, when you're done. Remove any obstructions, like exhaust, transmission lines etc. that will prevent the pan from coming down, If the axel is in the way, and the pan can't be slid out you may have to get bigger stands and lift from the frame to drop the axel down farther. If you do BE CAREFUL.

4

Remove the bolts around the oil pan, including the big ones in back. The pan will usually be stuck on very tight. Try hitting it sideways with your hand first, and at most a rubber mallet. Don't dent the pan. Sometimes you have to cut the sealant loose with a long razor.

5

* The oil pump will be at the back of the motor. It is easily identified, because it has a pickup tube and filter on it that dip down into the pan to suck up oil from the pan. It is usually held in place with only 1 bolt, and has no gasket, or sealant. It is held in correct orientation with a pin. After removing the bolt it should pull out easily. Put the new pump on. You may have to use the pickup tube and screen from the old one. Align the pin in its hole. Make sure the drive spline at the top lines up with the drive that comes down from the cam gear. Use no sealant inside the engine ever. Put the bolt back in, tighten to about 35-40 ft. lb., or about 1 flat past hand tight.

6

* Scrape the old gasket off the oil pan, and clean the oil pan well. Use a small, and I mean small amount of gasket glue to hold the gasket to the pan. It should be oil and residue free for the glue to stick. Scrape the old gasket from the engine block, it too should be relatively oil free at the face where the pan will mate. Some gaskets require a small, and again I mean small amount of silicon RTV black where the cork meats the rubber seals. If the sealant squishes out more than about 1/16th of an inch you used to much, clean it off and start over or the gunk that squishes into your engine will have you hunting a new oil pump again soon.

7

After the gasket glue has set, about 30 mins to 1 hour. Put the oil pan back in place, CAREFULLY as not to move the gasket around. All the bolt holes cut in the gasket should stay lined up. Start 2 bolts at opposing corners to hold it in place until you get all the other bolts started. Start all bolts by hand, you do not want to know the headache of helicoiling an engine block from a crossed bolt. Tighten all bolts, about 30 ft. lb., or a little more than hand tight. DO NOT OVERTIGHTEN, pan bolts are usually small and will break off if over tight. Trust me if you did your cleaning job right it won't leak. If you do get a small leak after a few days. Go back and retighten the bolts a small amount.

8

Put the drain plug back in the oil pan, put any exhaust, or lines you moved back the way they were. Lower the truck back down the reverse of how you raised it. Use the jack to get enough slack on one stand to lower and remove it then let one side down and repeat on the other side. Put new oil back in, and a new filter is a good idea, fill to the full mark on the dipstick. You're ready to go!