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No Oil Pressure -- pulling the engine.

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from my last thread, I do get some compression, but no oil pressure. I cranked the engine, spark plugs removed, cranked for over a minute, no oil pressure. So I took off the oil pressure sender to pour some oil down through the galleys, I tried to pour some oil but the oil sender hole fills up and I can't pour any more oil, and it only takes about a small "salsa" container full of oil anyway. So I figured, let's start at the oil filter housing. The oil filter is next inline after the oil pump, so I took off the oil filter housing, and there was absolutely no oil in the passage from the pump to the filter housing. so all this time I have been cranking the engine, no oil was being sucked by the pump... I don't want to damage the motor by cranking the motor any more than I need to without any oil so I guess my next plan of action is to pull the engine.


I have no choice as I do not want to Fubar the engine just attempting to prime for oil. who knows it is possible that the oil pump sprocket nut came off, or the pickup tube is completely clogged.. anyway that is what I decided... It's scary to turn over the engine, and crank for over a minute and no oil at all, not even at the oil filter housing, so something is causing the pump not to suck... haha 

... so now down the rabbit hole I go... wish me luck....


I'm planning on pulling it this weekend...


Larry F in Ca.




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Perhaps Mike meant the oil pump pressure piston? 

 I don't see how the chain tensioner would be a factor.

Maybe a worn pump is taking a long time to prime. A catastrophic pump failure would have become obvious before this I would think. Did you ever have it running?

Best to pull the pan and check the pump innards. Maybe a bearing too.

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7 hours ago, Hans said:

Perhaps Mike meant the oil pump pressure piston? 

Yeah, that's exactly what i meant.  A combination of old age and late night conspired to confuse the two...


It's been my experience, though that short of a broken chain or other catastrophic failure, those oil pumps are very long lived.  I measured the wear on one with 204k miles and there wasn't enough to measure.  Had I done a quick skim on the aluminum base where the two gears rotate, it would have been back to stock measurements.  


Post what you find so it can be a learning experience for us all.




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Ok, I HAVE to ask this-

you do have a pan full of oil, right???


If it won't pump oil out the filter boss, then there is something wrong with the pump or the pickup.


You CAN also try priming the pump that way, if you have a newer block with

round holes in the boss- a bit of vinyl tubing of the right OD and a funnel,

and run oil down into the pump that way.  It SHOULD take a bit of oil, then

hold it in the funnel- if you left it that way overnight, it would slowly leak down

into the pan.



Since  you've tried everything else, collect up all the 

old bottles of oil you have lying around that don't really

go to anything, and that you may never use, and add about 4 of them.

Then try again with the starter.  This should get oil right up to the pump itself.

Don't run it this way, of course- we're just trying to get you primed without

invoking Jeff Bezos- level evil.


And if THAT don't prime your pump, I dunno what will.


Then yes, out with the motor. 


I have an oil pump in the 'box of interesting failure' that has a cut in the pickup.

It's right below the 'high' oil level- and it's RIGHT in line with where the dipstick got

snagged by a crankshaft counterweight and whacked repeatedly against the pickup.

("So, like, my engine's making this noise, right, and I took a video from inside the

car with me listening to Jazzy Jeff, and, like, so, what is it?")



that sucks.  No, wait, no, it doesn't.

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thanks for the reply.. Yes.. i have oil in the pan.. thanks for asking... LOL.. I did an oil change, 20W-50..and put in about 4.5 quarts, checked my dipstick, right at the "high" mark, so definitely oil in the pan. I poured in some MMO about a small salsa cup ...you know the really small plastic cups used to serve salsa, ketchup, mustard.. well I was able to bend the cup to the point where it allowed me to pour the MMO and some oil in the left hole at the oil filter housing (looking from the driver fender) towards the passenger side, I poured oil and MMO down that hole (with the oil filter housing removed of course) till the oil started to overflow out of the hole, so I knew that there would be no more room for any more oil... I then filled the oil filter housing (with the oil filter attached) I filled it back up in both holes, till it wouldn't accept any more oil.. put the housing back on, tightening up all three attachment bolts, and then cranked the engine for about 1.5 minutes to 2 minutes, no pressure... So there has to be something wrong.


It hasn't run since 1993 or so... I did try to get it running in the mid 2000's but again life and other projects just prevented me from working on it.. now I have more time and money to throw at it... and of course now with the internet, I have more "knowledge" of what is happening. 



The engine was worked on back in 1991.. and I do have service records, but it was a small mom and pop shop, and i can barely tell from the carbon paper:

Valve Job

999.26 Bore/Hone

24 hot tank block

23 r/r piston

0 r/r bushing pin

22 resize rod

BMWO frees plug kit

obmw washer kit

024 0994 tensioner

bust out and flush Radiator

4-1990CC Bec 022.148 valve stem seal

bp5ES spark plugs

Surface flywheel

notes: Rebuild the engine + check the air conditioner

All that for $1655 back in 1991


I would bet that it was just a hone job, and a re-ringing of the pistons... and basically a valve job and new head gasket. as my friend ( I bought it from my high school friend) he blew a head gasket.. also the hone job was only like $28 bucks, so I'm going to assume it was a simple honing of the cylinders.. I'll soon find out when I dig into this engine..


Back to 2021....

the one thing that I didn't do is crank with the oil filter housing removed. when I removed the oil filter yesterday to fill it up with oil, I didn't mention that there was no oil in that hole, and it accepted about 5 to 6 "salsa" cups about 2/3 full of oil, so oil wasn't even getting up to fill up the oil filter. So there must be something going on preventing the oil to get sucked up...


My gut instinct is to pull the engine, cause continuing to crank an engine that has been sitting for upwards of 20 years, and not have oil pressure, well that I'm sure is not good on the bearings..



Edited by larry_in_socal
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Oh, and I forgot to mention, no where does it mention what they did with the oil pump, did they put the o-rings as needed? what about loctite on the oil filter sprocket ? I think there are too much unknowns here. BUT and that is a big but... lol.. my friend did have it running, and it ran but he could never get it running right after the rebuild, he bought a new carb trying to fix the car because it just wasn't running right, so he got mad and ended up leasing a new jeep back then.. so i bought it from him way back in 1993... and it has been parked in a garage for 7 to 8 years, before coming home to me and living under a tarp and car cover for the majority of it's pathetic life here with me... trying to make it right, the car deserves to be worked on and back on the road.... you understand.

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Agree with Toby. All the same symptoms as you, and I cranked with oil filter off, oil came out, reinstalled filter, cranked a little more, got oil pressure. On a motor that had been sitting a long time.


If you want to pull motor later, you can, but this is an easy procedure and it seems very likely you will see oil. 

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