How do you change the oil pump on a GM 3.4 liter engine?

Answer 1

For a reference mine is an 02. I found some of the information helpful online but there was a lot of information that was either way too much or lacking some important facts so I figured I would weigh in..

CAR REPAIR 101 REMOVE NEGATIVE BATTERY CABLE BEFORE PERFORMING ANY WORK.

1. Jack up the front of the car and support with jack stands spaced far enough apart to lay between them. You will need enough room to get your whole body under the oil pan comfortably or you will regret it.

2. Remove oil drain plug and start draining oil, let it drain and drip while you complete the other steps to help alleviate the mess when you pull the oil pan.

3. Remove serpentine belt, release the belt by flexing the tensioner and remove belt from the pulleys, you can just let the belt hang in place, no reason to remove it completely.

4. Remove the front passenger side tire and the plastic dirt shield behind the tire, you will have to remove both pieces. The one behind the tire will not come out without removing the one under the front corner of the bumper.

5. Remove bolts from the upper motor mount where it mounts on the fender so the engine can be lifted off of the rubber mount.

6. Remove bolts from the air conditioning pump and secure it out of the way toward the front of the car so as not to stress any of the lines or wires.

7. Remove the bolt from the front transmission mount, this is absolutely necessary as you will not be able to jack the engine up high enough to get the pan out with the mount in place.

8. Remove all oil pan bolts, there are a couple tucked away back in the dark corners between the motor and transmission, also there are 6 13mm bolts along the sides of the oil pan a couple inches from where it connects to the block, they are tucked into the indentions on the sides. Not sure why they are there but a few of them suck to get out.

9. Jack the engine up to allow enough clearance to remove the pan. I used a bottle jack and lifted the engine by the harmonic balance. Use a piece of wood on top of the jack to protect the balance pulley. As you lift it the back of the pan will drop down so you can slide it past the transmission once you have enough clearance so it does not catch on the front main cap.

10. Remove the pan inside of the oil pan that covers the rod/main bearing caps.

11. Remove the oil pump and install a new one in its place. Be sure to have the pickup tube pressed into the new pump or secure it extremely well or it may drop off during operation from heating and cooling...don't ask me why I know this...

12. While you are in there you may want to drop the main and rod bearing caps and inspect the bearings, after all if you are replacing the oil pump there must be a reason for it and the bearings will bear the brunt of the low or lack of pressure...

*Note: You can replace the bearings without removing the crank and you might as well while you are in there anyway.

a. Remove all spark plugs to relieve pressure in the cylinders as you move the pistons up and down to access the bearings. (pay very close attention to location and orientation of the bearing caps for rods and mains as they HAVE to go back on the same way.)

b. Remove all rod bearing caps, you will have to let the motor down onto the mounts and spin the motor by using a ratchet on the balance center bolt to get to all of the rod caps.

c. While moving the crank around you can access all of the piston rods and get the upper bearings from the rods.

d. Remove all of the main bearing caps and remember location and orientation as they HAVE to go back in the same exact way.

e. Slide the upper bearings out around the crank lobes so you can slide the new bearings into place. The way I did this was to hammer an old rod bearing flat and grab it with vice grips by the end. Slather the other end with assembly lube and use it to tap the bearing around the lobe as far as you can, it will bend around the lobe without damaging the surfaces as long as it is clean. Once the bearing is half way out you can use a screwdriver or a long punch to tap it from the backside of the bearing the rest of the way out.

f. Slide new main bearings into place by slathering them with assembly lube and sliding it as far as you can around the top of the lobe by hand and using your fancy removal tool, flat rod bearing on vice grips, to LIGHTLY tap it into place, they are aluminum and will damage easily so be careful.

g. Replace main bearing caps with new bearings inserted, again slather with assembly lube. Torque to specs.

h. Replace upper and lower rod bearings and caps slathered with assembly lube. Torque to specs.

*Bearings are done...

13. Replace bearing cover, pan, and all other items in the order they came off.

Hope I didn't miss anything but I tried to add enough detail to show the issues that held me up while removing my oil pan for the first time...Good luck.

Answer 2

To change the oil pump on a GM 3.4 liter engine, remove the throttle body to gain access to it. Remove the hold down and grab it with very large pliers. Twist a few times and pull straight up. Replace the oil pump.