'90 2.4 oil pump replacement

[royster]

The reason you have to drop the oil pan is because the oil sump pick-up is bolted onto the oil pump in there.

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Drain the oil, and while it drains, you can make use of the time by wiping off the grease from around the 5,742 oil pan bolts you’ll need to remove. If you didn’t de-grease the engine compartment, you might want to take this time to at least wipe off the cross-member frame under the engine, because you’ll be reaching through there a lot. It’s that, or keep washing your hands and forearms from all the grease you keep getting into. Your choice.

I did not have to raise the engine to get the oil pan out, though the book says you might need to do so. The oil pan is bolted into the oil pump plate, so it has to be unbolted before you start unbolting the oil pump plate…at least, this is a sure-footed approach. It’s all gotta be done.

Once your oil is drained, remove the oil pan bolts and save them in a plastic bag or container. As I mentioned earlier, I made a cardboard holder for them, only to find they’re all the same length. I could be wrong about that so pay attention as you remove them. Dropping them all into a tin can with cleaning solution makes for a clean re-assembly, then let them dry, then bag ’em.

Use a wooden block to tap the sides and front of the pan with a hammer (don’t beat on the pan directly with the hammer). This helps loosen the oil pan gasket or sealer. You don’t want to pry the oil pan lip, because if this action bends the lip, you’ll get a serious oil leak there. To keep the oil pan mating surface true, try your best to knock the pan off its mounted position with tapping it. If that doesn’t work, a very thin putty knife can be carefully used to wedge around the lip of the pan. Beyond that, you might consider explosives.

Once the pan is off, it can be cleaned and stored. Clean the mating surfaces real good with acetone. When dried, I applied the silicone sealer and set the gasket. I got the gasket in place with the sealer on the pan, then flipped it upside down and put it on the workbench surface, applying pressure to assure an even seating of the gasket. Then, flipped back up, I insured each and every hole lined up. I set it aside to allow the silicone to set. The gasket didn’t slip or fall off as I re-installed the pan, and as MY job is now completed, I can assure you I have no oil pan leaks. So this approach should work for you.

Remove the two bolts holding the oil sump and remove the sump. Yuck! Whatta mess! Get that thing cleaned up, back-flush it and spray it with brake parts cleaner (unless you opt to install a new one). I found a couple boogers inside the screen, and worked to get them out. Remember: this sump is all there is to keep particles and dropped bolts from entering the oil pump. Oil doesn’t get to the filter ‘til after it goes through this sump. Make sure it’s clean, and that includes the mounting surface, which likely has gasket material on it.

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It’s time for another cardboard bolt holder, and this one is for your oil pump plate bolts. Since, in theory, you HAVE the new pump there, you can actually just trace the bolt holes right from the pump itself, onto the cardboard. Poke the holes with a poinky object and enlarge them with needle-nose pliers. You want them about ¼” wide. Make a seperate area on the cardboard...lower left-hand side...for the five bolts that come off the oil filter unit. Designate a separate hole…sort of like a mistress…for a single bolt (it couldn’t find a date) off to one side. We’re about to discuss this mystery bolt and the reason for its being.

Here comes another crucial point that is missing from my manual: the nut that holds the mysterious Silent Shaft. And the conspiring bolt that protects the Cave of Ali Bubba…he’s the redneck version of the Arabic story. Facing the engine, there is a bolt on the right-hand side, back there near the starter. This bolt is how you access the Silent Shaft secret society.
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Remove the bolt, and try to get a phillips screwdriver into that hole. Dinner and drinks might work, with a few personal complements thrown in, but since the timing belt is off, it’s perfectly okay to turn the oil pump gear and get that shaft to turn. Get a feel for it: regardless of your heterosexual inclinations, you’ll be handling The Shaft a bit more during this operation. It’s okay: everybody does it, but no one talks about it. That's one reason it’s CALLED a Silent Shaft, based on secret society principles.

Place that bolt in the cardboard holder in that designated single spot.

Turn the shaft until the screwdriver goes all the way in, and when you turn the oil pump gear back and forth, you can feel it bump against the screwdriver. Leave the screwdriver in there, for now.

Camoit provides us this great photo, of a crucial step: removing the vault door to the Silent Shaft Treasury. Actually, it's an access panel to the nut that holds the balance shaft in place. I used a nail-set and hammer to tap it counter-clockwise in order to remove it. Camoit suggests a center punch. At any rate, it comes off so you can remove the nut hiding behind it.
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Note the plate has an "o" ring, and the replacement ring SHOULD be in your oil pump kit. Play it safe and retain the old ring, for now.

You left the screwdriver holding the silent shaft because that's how you're going to get that nut loose: holding the shaft in place as you turn the nut counter-clockwise. Your kit may or may not have a replacement nut...next election is 2016...but save it just the same. Instead of a hole on your cardboard holder, use a screw through the nut to attach it to the cardboard...maybe near the lonely Silent Shaft bolt that can't get a date. Also be very sure to keep that cover in a place it won't get lost. As an oil seal, it's a small but crucial component. Perhaps in a sandwich bag, taped to the cardboard bolt holder.

Removing the oil pump plate bolts:
As you’ll notice with so many of the manual’s instructions regarding component removal, starting from the outside, working toward the center seems to be the theme. The reason for this is the more pliable aluminum parts against the iron block tend to have a slight curve to them. The aluminum has some “give” to it, and assuring you’re not stressing the part allows this ’give” to not become “break” or “crack”. ¼” turns are recommended for each bolt, one at a time, several times, until the bolts are finger-loose, then you take them all off, placing them in their cardboard holding cells. This isn’t so important on a part you no longer intend to use, but it IS important when you go to install the new part, which will be a reversal of this procedure. You will install the bolts starting from the center, working your way outward.

Nit-picky details -
... did you disconnect the oil pressure sending wire? It's near the oil filter. It gets lots of oil and grease, so spray it clean with some electrical parts spray or brake cleaner spray so oil doesn't short it out. Inspect the wire for breaks and electrician's-tape it up if you need to.

... was your oil guage/light working? If not, get a replacement sending unit.

...if you haven't done so, remove the oil filter.