CJ5 258 81 Oil Pump replacement help - JeepForum.com
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post #1 of 15 Old 07-21-2021, 09:45 AM Thread Starter
TheFlynn01
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CJ5 258 81 Oil Pump replacement help

Hello everyone! Just as I was getting ready for some vanity projects for my CJ, I think my oil pump is plugged or going out or something. As it seems to be giving consistently high oil pressure, peaking out at the 80, then when idle is sits at the 50-70. When I first got the Jeep I was used to it idling low around the 20 and then going up and down through out driving. So seeing it so high, and staying high makes me thing it needs tome work.

Now I have heard that on the 258 I6 the motor needs to be pulled, or lifted with a cherry picker to get the oil pan off to look at the pump. Is this true?

If so, I have a friend who has one from his dad, however he has no idea how to do that, nor do I. So, I seek info from those who went before me, to see how I can go about this and if the pump is going or what you all might think.

Thanks!
Mike

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post #2 of 15 Old 07-21-2021, 10:00 AM
Matt1981CJ7
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Are you relying on the notoriously faulty factory oil pressure gauge?

If so, it might be worth hooking up a mechanical gauge to confirm the high oil pressure before you go to the trouble of replacing the pump.

The 258 requires removing the oil pan in order to remove the oil pump. The oil pan removal requires temporarily supporting the engine, then removing the passenger side motor mount before removing the pan. The whole chore should not require lifting or removing the engine,

Matt
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post #3 of 15 Old 07-21-2021, 11:21 AM Thread Starter
TheFlynn01
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Hey Matt!

I did not know they are notoriously faulty, but I am relying on that, as well as the strange lugging that took place when driving it. I was going about town when I lost speed for a moment and the engine seemed to be sluggish and the oil pressure went way up. How might I check the oil gauge?

How would I support the engine to take the pan out? Its good to know I wont have to pull the whole thing, but I would like to know how to keep it from falling if I have to get under it. I wouldnt mind going down there anyway as the oil pan had its plug stripped ages ago, and is pretty beat up. So I figure it might just be good to get it done now, especially with the weird way things were acting.
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post #4 of 15 Old 07-21-2021, 12:12 PM
Matt1981CJ7
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I think the factory oil pressure gauge can be tested, but that goes beyond my electrical pay grade, Perhaps John Strenk will chime in with the "how to" on that.

Most guys just hook up a mechanical gauge via the same port that the factory oil sender is located.

I'd stick a floor jack under the transmission skid plate, near the trans mount, to support the engine while you remove the passenger motor mount, oil pan, and oil pump.

Matt


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post #5 of 15 Old 07-21-2021, 12:24 PM
devildog80
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This works great.
Top pic is another members method, and I did the same with a piece of angle iron off an old bed frame.
Second pic, mine would be just off frame to the right, as this rests on the top of the frond axle pumpkin.
Just changed out oil pump for HV about a month back.
Attached Thumbnails
1A Engine%20Support%20(2).jpg   20210523_144908.jpg  
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post #6 of 15 Old 07-21-2021, 02:28 PM
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Most folks worry when their oil pressure drops to zero or slightly above. Ours would hit 60 PSI when the heater fan switch was on low and peg when the fan was on high. The battery would die in three days. Jep it had a draw. It didn't go away when I killed the power to the fan so the culprit was by process of elimination either the oil pressure gauge or the sender. Replaced the electric gauge with a mechanical one and the oil pressure and battery life returned to normal.

On a recent oil change I bought 10W-40 high mileage oil instead of normal 10W-30. Upon startup the oil pressure was much higher but returned to a normal 20-25 PSI at idle after warming up.

There are other things that affect oil pressure than the oil pump. Have you changed the weight of the oil or the brand of oil filter recently?

As suggested a mechanical gauge is an economical and reliable replacement for the OEM gauge. Making a hard job out of what could be an easy fix or throwing money at a problem in hopes that it works may not be the best course of action especially when you aren't certain what the problem is.

Good luck!

-----

Paved roads are prime examples of government over spending!
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post #7 of 15 Old 07-21-2021, 07:47 PM
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Cheap

You can get one of these

https://www.wdesertraja.com/index.ph...ducts_id=55077

Or you can get one with like 3 gauges (if it's cheap) as a test, you will only use the oil pressure one

Hook it up with in the oil pressure port and simply route it under the hood and thru your door/ window (it's temporary) lay it on the seat/ tape it on top of the column.

It may be possible your oil filter may cause the higher pressure??? What about a problem with the oil bypass/ at the oil filter.

Just a quick lifting of the ole motor

It's a good idea to take the exhaust loose so you don't bend or break it.

Jeep stays on ground

With a 258, one must lift it off of motor mounts about 2 inches-----Lets stop where you need to, don't over lift it and break stuff----take the bolts out! If you lift with it attached, surely you will break the bell housing!!!

You can use a jack in place of my jack stand to lift it at the bell housing

Use wood cushion the "push" see my pics.

While you are in there---maybe a high volume oil pump will make the engine last??? Rear main seal? a new type pan gasket (holds the pan up while you start your bolts)

Things to ponder

Ask for help if you need it....we don't mind!

------JEEPFELLER
Attached Thumbnails
oilgauge_2_a98d129ecfbb86124d815a048c28404f2bebe46f.jpg   SUPPORT BELLHOUSING-TRANNY TRANSFER CASE WEIGHT--WHEN I DROP THE SKID PLATE.jpg   oil bypass bb.jpg  
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post #8 of 15 Old 07-21-2021, 09:10 PM
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It would not produce 80psi at idle even with a completely blocked exit from the oil sender. The oil sender/sensor is after the filter, further along the oil gallery, so a blocked filter or strainer would give 0 psi, not 80 psi. It is possible a relief valve blocked open (or opening because the filter has collapsed) would give you higher pressure than filtered oil but I am guessing 25psi max.

By far the more likely culprit is the $20 gauge and/ or a short in the sensor wiring and/or short in the sender/sensor. You can get it to peg by touching the sensor wire to a ground.
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BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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post #9 of 15 Old 07-22-2021, 11:12 AM
John Strenk
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Also, if you drop the pan, get a one piece gasket for the oil pan and those 'thingies' that hold the gasket in place when you lift up the oil pan.



https://www.summitracing.com/parts/f...xoCufYQAvD_BwE



https://www.summitracing.com/parts/rnb-45722


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post #10 of 15 Old 07-22-2021, 12:13 PM
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I bought the same gasket from O'Reillys and had the guides in the box.
Also, there are (2) different size bolts holding the oil pan on. Tips from other JF members, use this method to keep the bolts organized, so each one out goes back in the same hole. Example is another members pic when they worked on timing set replacement. When doing work on older rigs like ours, it is key to keep the bolts/nuts/keepers matched up where they came out of, as the threads have been "living" in that space for many years, they work better to back to that same place.
Just an old piece of clean cardboard, use a pencil/pen/marker and draw a diagram of the pan and where each bolt is located. Punch a small hole at each bolt location, then when you take out a bolt, just screw it into the cardboard at the labeled location.
Before starting removal of the pan, get under the truck and look at the rear of the oil pan area inspection cover for the bell housing, and note there are little tabs at the top of it just under the lip of the pan. When you get ready to drop the pan, these can be moved with a flat screwdriver, so the pan will clear the cover and come down. On install, these tabs will assist you in holding up the back of the pan, as you simply push the back of the pan up past these and will be held there so you can start your bolts back into the block.
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MR. JEEP TIMING SET 147.jpg  
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post #11 of 15 Old 07-22-2021, 03:33 PM
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Here's one from snatching my tranny.

I'd say the next better thing you can do is go online and purchase a factory service manual, a aftermarket manual is better than nothing, a factory manual is perfection for repairs and explanations.

Gotta take better care of them then I did!

------JEEPFELLER
Attached Thumbnails
TRANNY2 030.jpg   MOST OF MY JEEP MANUALS...TOP 2 ON RIGHT STAY IN THE JEEPS.jpg   MY POOR 1979 AMC JEEP SERVICE MANUAL...IT REALLY GOES INTO STUFF DETAILED..APPLIES TO NEARBY YEA.jpg  
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post #12 of 15 Old 07-22-2021, 09:39 PM
BagusJeep
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Unfortunately some of those manuals, including the Haynes, are printed on rough paper that would disgrace a newspaper. They just pick up oil. I had a factory original manual for a 1970s Triumph some years ago, and it had glossy paper that wiped clean.

And talking of Haynes, I went to their motor museum a few years ago when on vacation, down towards Yeovil in Somerset, England. Great collection of mainly worn driver quality cars, not the fancy shiny stuff that you never drove.

BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
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post #13 of 15 Old 07-23-2021, 09:54 AM Thread Starter
TheFlynn01
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Quote:
Originally Posted by devildog80 View Post
This works great.
Top pic is another members method, and I did the same with a piece of angle iron off an old bed frame.
Second pic, mine would be just off frame to the right, as this rests on the top of the frond axle pumpkin.
Just changed out oil pump for HV about a month back.
I will look that over and give it a shot!

Quote:
Originally Posted by bob4703 View Post
Most folks worry when their oil pressure drops to zero or slightly above. Ours would hit 60 PSI when the heater fan switch was on low and peg when the fan was on high. The battery would die in three days. Jep it had a draw. It didn't go away when I killed the power to the fan so the culprit was by process of elimination either the oil pressure gauge or the sender. Replaced the electric gauge with a mechanical one and the oil pressure and battery life returned to normal.

On a recent oil change I bought 10W-40 high mileage oil instead of normal 10W-30. Upon startup the oil pressure was much higher but returned to a normal 20-25 PSI at idle after warming up.

There are other things that affect oil pressure than the oil pump. Have you changed the weight of the oil or the brand of oil filter recently?

As suggested a mechanical gauge is an economical and reliable replacement for the OEM gauge. Making a hard job out of what could be an easy fix or throwing money at a problem in hopes that it works may not be the best course of action especially when you aren't certain what the problem is.

Good luck!
I have not changed the oil as far as I know. I have been using 10w-30 with a fram filter. The old filter was from napa. The pervious owner might have done the same but you never know. I will look into the oil gauge!

Quote:
Originally Posted by JEEPFELLER View Post
Cheap

You can get one of these

https://www.wdesertraja.com/index.ph...ducts_id=55077

Or you can get one with like 3 gauges (if it's cheap) as a test, you will only use the oil pressure one

Hook it up with in the oil pressure port and simply route it under the hood and thru your door/ window (it's temporary) lay it on the seat/ tape it on top of the column.

It may be possible your oil filter may cause the higher pressure??? What about a problem with the oil bypass/ at the oil filter.

Just a quick lifting of the ole motor

It's a good idea to take the exhaust loose so you don't bend or break it.

Jeep stays on ground

With a 258, one must lift it off of motor mounts about 2 inches-----Lets stop where you need to, don't over lift it and break stuff----take the bolts out! If you lift with it attached, surely you will break the bell housing!!!

You can use a jack in place of my jack stand to lift it at the bell housing

Use wood cushion the "push" see my pics.

While you are in there---maybe a high volume oil pump will make the engine last??? Rear main seal? a new type pan gasket (holds the pan up while you start your bolts)

Things to ponder

Ask for help if you need it....we don't mind!

------JEEPFELLER
Its nice to see another example of how to lift the thing without a puller these pictures are great. As The pan will need to be changed one day to stop the leak. The previous owner already installed an oversized drain plug so I figure it will be due to change one day. This is good info on how to check this stuff out!

Quote:
Originally Posted by BagusJeep View Post
It would not produce 80psi at idle even with a completely blocked exit from the oil sender. The oil sender/sensor is after the filter, further along the oil gallery, so a blocked filter or strainer would give 0 psi, not 80 psi. It is possible a relief valve blocked open (or opening because the filter has collapsed) would give you higher pressure than filtered oil but I am guessing 25psi max.

By far the more likely culprit is the $20 gauge and/ or a short in the sensor wiring and/or short in the sender/sensor. You can get it to peg by touching the sensor wire to a ground.
hmmm I will have to look at it. I feel more likely that its the gauge failing, or at least I need to check that first!

Quote:
Originally Posted by John Strenk View Post
Also, if you drop the pan, get a one piece gasket for the oil pan and those 'thingies' that hold the gasket in place when you lift up the oil pan.



https://www.summitracing.com/parts/f...xoCufYQAvD_BwE



https://www.summitracing.com/parts/rnb-45722
Those look super useful. I will be sure to get a set!

Quote:
Originally Posted by devildog80 View Post
I bought the same gasket from O'Reillys and had the guides in the box.
Also, there are (2) different size bolts holding the oil pan on. Tips from other JF members, use this method to keep the bolts organized, so each one out goes back in the same hole. Example is another members pic when they worked on timing set replacement. When doing work on older rigs like ours, it is key to keep the bolts/nuts/keepers matched up where they came out of, as the threads have been "living" in that space for many years, they work better to back to that same place.
Just an old piece of clean cardboard, use a pencil/pen/marker and draw a diagram of the pan and where each bolt is located. Punch a small hole at each bolt location, then when you take out a bolt, just screw it into the cardboard at the labeled location.
Before starting removal of the pan, get under the truck and look at the rear of the oil pan area inspection cover for the bell housing, and note there are little tabs at the top of it just under the lip of the pan. When you get ready to drop the pan, these can be moved with a flat screwdriver, so the pan will clear the cover and come down. On install, these tabs will assist you in holding up the back of the pan, as you simply push the back of the pan up past these and will be held there so you can start your bolts back into the block.
That looks like a super good idea. Nice way to keep it all together!

Quote:
Originally Posted by JEEPFELLER View Post
Here's one from snatching my tranny.

I'd say the next better thing you can do is go online and purchase a factory service manual, a aftermarket manual is better than nothing, a factory manual is perfection for repairs and explanations.

Gotta take better care of them then I did!

------JEEPFELLER
I do have a manual but as I am new to all this I sometimes get confused, thats why this forum is so nice to have!

So As it looks like it will be good to check the gauge, any good videos on how to pop it out and replace it?

Thank you for all the info here! Its has been superhelpful, I feel like I can move forward with more of a direction!
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post #14 of 15 Old 07-23-2021, 08:50 PM
JEEPFELLER
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One more stupid thing that happened at my place!

Somebody decided to use the bottle jack on the bottom of the oil pan.

What happened next was "Jacking--pushing" on the little skid plate (thought it might be stronger--beings it is a "plate")

Maybe the plate was OK---but it shoved one of the four "Spot welds" up into the actual pan part.

It leaked pretty darn good until I removed the oil pan and brazed the new tear closed.

Moral????

Don't jack on the oil pan!

-----JEEPFELLER
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post #15 of 15 Old 07-24-2021, 06:50 AM
John Strenk
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Quote:
Originally Posted by BagusJeep View Post
Unfortunately some of those manuals, including the Haynes, are printed on rough paper that would disgrace a newspaper. They just pick up oil. I had a factory original manual for a 1970s Triumph some years ago, and it had glossy paper that wiped clean.

And talking of Haynes, I went to their motor museum a few years ago when on vacation, down towards Yeovil in Somerset, England. Great collection of mainly worn driver quality cars, not the fancy shiny stuff that you never drove.
Yes! I had a 1968 TR-250 manual and I remember the paper was glossy and I think punched for a ring binder.

I also had a shop manual for a NSU TTS and it was also printed on glossy paper. Unfortunately it was all in German. But I figured it out.

The last manual I bought was for a Renegade. It came on a plastic credit card. At least I could print out the pages I need and throw it away when I'm done or just look at them on my iPad.


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