1980 Jeep CJ5 Oil Pump Repair - Oil Pan Removal

Good Day All;

I have a 1980 Jeep CJ5 and need to replace/repair the oil pump. To do so I am told by my trusty Chilton manual that I am to remove the oil pan to do so. From what it says I’m hearing I need something akin to a cherry-picker to secure the engine. As I am pretty strapped and have been doing repairs myself I was wondering if that was necessary and in addition if someone would be so kind as to provide a step by step list as to what to do I’d appreciate it.

Thank you in advance for your time and guidance.

Roy Rogers Maine

(note: I LOVE how with a manual, the internet and a decent force-of-will you can make almost any repair needed…and how the CJ gives you the confidence to do so)

What can sometimes be done is, remove the motor mount bolts.

Using a floor jack, lift the engine at the crank pulley as high up as it will go.

Place pieces of 2X4 in between the motor mounts and brackets to hold the engine up.

Remove the jack.

Remove the oil pan bolts and drop the oil pan.

Reach inside the oil pan and remove the oil pump to engine hardware and allow the oil pump to fall into the oil pan.

Using a breaker bar and a socket, turn the crankshaft by hand so the lobes of the crankshaft move out of the way so the oil pan/pump can be moved forward for removal.


Those instructions are straight from the Shade Tree Expurt’s Manual @tester. I dropped a few oil pans working in the family driveway 50 years ago and never failed to be finished and have the driveway cleaned up by dark. It’s been so long I don’t recall where I learned the trick.

Tester’s idea seems like a good one for a driveway diy’er.

Here’s something else to add to your bag of tricks. No experience w/you make/model, but when I change the timing belt on my Corolla I have to remove/loosen the mounts and lift the engine a bit to gain the needed access. I pull from above, rather than jack from below. I made a wooden beam gadget that rests across support braces inside the engine compartment, with through J-bolts that attach to the engine support points, I tighten the corresponding nuts to raise the engine. I sometimes have to jack from below too at some point, but that’s not to raise the engine so much as to position it at the angle needed to reconnect the mounts.

I believe Harbor Freight makes a similar thing, but probably better, in steel box beams rather than wood. Yeah, here it is, “engine support bar”, $80. Best of luck.


So why do you think the engine needs an oil pump? Is it because of low oil pressure?

If so, pump replacement is seldom ever the answer.

@Tester … just curious about your method. It would never occur to me to lift the engine at the crank pulley. I’d worry it would damage the pulley (& harmonic balancer) or bend the crankshaft or damage a crankshaft bearing or seal. Is that stuff rugged enough to lift the engine with, presuming it is only the engine and you don’t try to lift the vehicle too?

OK4450 expressed my own thoughts. Low oil pressure is very rarely due to a worn out oil pump. The oil pump is imprecise mechanically, most are just like two interlocked gears with spaces between them that move fluid as they turn… like a slice of the insides of a roots-type blower… and they’re continuously flushed with fresh oil. They’re pretty much the last thing to wear out.

But there are other common reasons for poor pressure, usually worn bearings. The pressure is created by the pump forcing the oil through the small spaces that are the clearances between the sleeve bearings around the crankshaft, the connecting rods, and the cam bearings and the respective surfaces of each. If these spaces wear too large, the pump has difficulty maintaining pressure. It’s kind of like trying to keep the pressure up on a balloon with a pinhole in it. Typically the low pressure will show up first at idle, where the pump internals are turning their slowest.

So why is it that you believe you need an oil pump? Please respond… it may be that you’re planning to do a lot of work and spend money to no avail. Your Jeep is 35 years old. It’s highly likely that the oil pump is not the source of your problems. Perhaps we can help.

I’m with OK4450 and TSM, the pump is likely not the problem, but the bearing clearances as they said.

A lot of work to find out it had no effect.


Pull a couple of bearing caps while the pan is off and check for wear.