As some of the people who read my build thread know, my Jeep has not had the engine ran in probably 10 or so months. Probably even closer to a year by now, as I fully parked it in August last year beginning with my rear bumper swap, which turned into a whole fuel system swap, clutch, timing cover/chain, rear main seal, oil pan project.
I finally cranked the engine up for the first time about a week ago. Immediately, it did not sound good. I heard a ticking noise (worse than the usual 4.0 tick that everyone has). I figured it was just working up some oil, no big deal, noise would go away quickly. Shut it down and went into the house to give it some time before I'd crank it again. An hour or so later, I went back out there and cranked it up again. Noise was still there. I peek around at the gauges and !!! - no oil pressure. 0. Not low, just none at all. I know my sender is accurate too so not a sender/gauge issue.
I shut it off and start fretting about the possible damage I did, and then transfer over to the problem solving mindset, trying to think of all the possible causes and what my next steps would be. Oil was definitely in it, so it's not a no-oil situation. I pulled the oil filter, which I had recently changed. Bone dry (I usually install dry or pre-fill with a small amount, enough that the filter absorbs it all). Filter was completely dry, so I put it back on. The filter is the first spot the oil goes after being sucked out of the pan, so obviously oil is not leaving the pan at all if it's not getting to the filter.
My buddy brought up the idea that maybe my oil system needed priming since it had sat so long. I was doubtful, mainly because I thought the engine would have immediately pulled up oil after being cranked up. Wanting to rule out this possibliity, I pulled the ASD relay, the fuel pump relay, unplugged the ignition coil, and removed all the spark plugs (for easier cranking). I cranked the engine a bunch of times, which spun real easily with everything removed. Still no pressure, nothing at all. Figuring priming wasn't the issue, I left the ignition stuff taken apart and started looking towards the pan/pump/pickup tube, etc.
I drained the oil and went and grabbed dinner while I waited. Next I zipped all 20 something bolts off and dropped the pan. My existing pickup tube was a little bit dented, but that is from a past life. Young 17 year old me didn't know what he was doing when he changed motor mounts in 2013. Young me used a jack directly on the oil pan and it dented the old pan enough to actually press into the oil pump pickup tube shield and bent it a bit. Never caused oil problems though so I ran it.
When I started examining the pickup tube, it looked like the screen was somehow sucking up against the top part of the pickup. Wondering if that was blocking suction, I ordered a new pickup tube and compared. Nope, they were basically the same looking. Returned the pickup tube and continued on in my search.
I stuck a bucket of oil under the pickup and submersed it down in there. Cranked the engine again, no suction. I wanted to rule out the pickup tube vacuuming itself up to the aftermarket oil pan and causing a loss of oil suction. Nope, no dice.
Next I pulled the oil pump to test it by itself. I dipped it in a bucket of oil and spun the drive with a drill. Nothing. Checked the drive and the distributor tip which drives the pump. Both were in great shape, no broken parts. I disassembled the pump and everything looked perfect. It's hard for a gear oil pump to die, they basically just spin forever and ever. I put the pump back together.
Okay, so what the hell? What could it possibly be? I kept playing with the pump in oil and I noticed hole in the top that didn't correspond to anything in the engine block. Since that hole would be plugged theoretically by the gasket, I plugged it with my finger to simulate installation. I spun it with the drill again, boom, after 5 second oil started coming out of the top. So obviously the old pump worked.
When I did my rear main seal, I wanted to change the dented pickup tube. The pickup tube has a bracket on it that overlaps one of the pump's mounting bolt holes. To try and change the pickup, I removed that bolt. I started yanking on the pickup tube to try and remove it and decided to abort the mission, as I didn't know how hard it would be for me to press in a new pickup tube after the fact. I put the bolt back and forgot about that idea. Fast forward to now, after discovering the hole in the pump that has to be plugged, I wondered if maybe me removing the oil pump bolt in the past ruined that gasket and now the hole wasn't plugging properly, hence no suction?? You can see the bulge where the empty hole pressed against the gasket, so I was wondering if me removing that right side bolt for the pickup tube and then reinstalling possibly screwed up the gasket sealing with that hole, hence losing suction.
So, I ordered a new pump, pickup tube, and gasket. With all of this I figured new parts are best. I tested the old pump in some nasty oil too, so getting a nice new clean part to work with seemed like a good idea. Today I got all the parts:
Melling M81A Oil Pump
Melling 242S pickup tube
Melling MCAT-62 install tool (highly recommended!!!!!)
Fel Pro Oil Pan Gasket
6 more quarts of stupid oil after I just wasted the last 6 quarts
Nice new pump and pickup tube pressed together...
I pressed in the pickup tube and went to install. Everything went right on. I went to crank the engine with the starter again, with the pickup tube dipped in oil. Lo and behold.......still no freakin' oil pressure. After nearly yanking all my hair and setting the Jeep on fire, I decided to sit and think. The only thing I hadn't done yet was truly prime the engine with a drill, flat blade screwdriver, and do it through the distributor hole. I didn't want to but I decided to pull the distributor and go to harbor freight for some screwdrivers that I could chop up and stick in my drill. I got this bad boy stuck in the drill and did some pumping.
After something like THREE minutes, I FINALLY got oil pressure. I was monitoring the oil through the filter spot. I removed the filter. The oil gets pumped to the filter first, so as soon as oil came out of the filter hole I knew. Then I put the filter back on, put the oil pan, starter, etc on. I filled the oil pan up with 6 quarts of oil and did a crank with the starter. Finally, some damn oil pressure when cranking! I could have sped this process up by packing the oil pump with vaseline, but I didn't want to open up the brand new pump because it has a gasket in it that I didn't want to mess up and then introduce more questionable areas of possible failure.
Pic of the oil pump that you "spin" with the drill from above. You stick the flathead screwdriver into here and run the drill clockwise, simulating the job the distributor usually does.
I buttoned back up all the ignition stuff, ASD relay, fuel relay, etc. I gave it a quick prayer and started it up. 50 PSI oil pressure!! It sounded great and was idling smooth as a YJ engine can.
So the moral of the story here is that it wasn't any of the millions of things I checked. It was seriously that the system was empty and needed priming, and all the starter usage was too fast to actually begin sucking up oil. What I should have done from the beginning was pull the distributor, spin the pump with my drill and screwdriver, and I would have built up pressure and never had to change the pump, dropped the pan, etc. Oh well, you live and you learn.
Really, there are two morals. The first moral is to run your engine more often so this never happens. The second moral is to check and try truly priming the oil pump in case the system ran dry. Had I done all that to begin with, life would have been a lot easier. The better plan though is to run the engine often enough so the system doesn't go dry.
I finally got my new Mopar spark plug wires too so I went ahead and installed them today after the engine was running properly again. What a damn mess. At least I know I have a good oil pump and pickup tube now!
Thanks @SirDoopYJ and @jeepjoe43 for letting me vent a small bit while I worked through the process trying to figure it all out lol.
I finally cranked the engine up for the first time about a week ago. Immediately, it did not sound good. I heard a ticking noise (worse than the usual 4.0 tick that everyone has). I figured it was just working up some oil, no big deal, noise would go away quickly. Shut it down and went into the house to give it some time before I'd crank it again. An hour or so later, I went back out there and cranked it up again. Noise was still there. I peek around at the gauges and !!! - no oil pressure. 0. Not low, just none at all. I know my sender is accurate too so not a sender/gauge issue.
I shut it off and start fretting about the possible damage I did, and then transfer over to the problem solving mindset, trying to think of all the possible causes and what my next steps would be. Oil was definitely in it, so it's not a no-oil situation. I pulled the oil filter, which I had recently changed. Bone dry (I usually install dry or pre-fill with a small amount, enough that the filter absorbs it all). Filter was completely dry, so I put it back on. The filter is the first spot the oil goes after being sucked out of the pan, so obviously oil is not leaving the pan at all if it's not getting to the filter.
My buddy brought up the idea that maybe my oil system needed priming since it had sat so long. I was doubtful, mainly because I thought the engine would have immediately pulled up oil after being cranked up. Wanting to rule out this possibliity, I pulled the ASD relay, the fuel pump relay, unplugged the ignition coil, and removed all the spark plugs (for easier cranking). I cranked the engine a bunch of times, which spun real easily with everything removed. Still no pressure, nothing at all. Figuring priming wasn't the issue, I left the ignition stuff taken apart and started looking towards the pan/pump/pickup tube, etc.
I drained the oil and went and grabbed dinner while I waited. Next I zipped all 20 something bolts off and dropped the pan. My existing pickup tube was a little bit dented, but that is from a past life. Young 17 year old me didn't know what he was doing when he changed motor mounts in 2013. Young me used a jack directly on the oil pan and it dented the old pan enough to actually press into the oil pump pickup tube shield and bent it a bit. Never caused oil problems though so I ran it.
When I started examining the pickup tube, it looked like the screen was somehow sucking up against the top part of the pickup. Wondering if that was blocking suction, I ordered a new pickup tube and compared. Nope, they were basically the same looking. Returned the pickup tube and continued on in my search.
I stuck a bucket of oil under the pickup and submersed it down in there. Cranked the engine again, no suction. I wanted to rule out the pickup tube vacuuming itself up to the aftermarket oil pan and causing a loss of oil suction. Nope, no dice.
Next I pulled the oil pump to test it by itself. I dipped it in a bucket of oil and spun the drive with a drill. Nothing. Checked the drive and the distributor tip which drives the pump. Both were in great shape, no broken parts. I disassembled the pump and everything looked perfect. It's hard for a gear oil pump to die, they basically just spin forever and ever. I put the pump back together.
Okay, so what the hell? What could it possibly be? I kept playing with the pump in oil and I noticed hole in the top that didn't correspond to anything in the engine block. Since that hole would be plugged theoretically by the gasket, I plugged it with my finger to simulate installation. I spun it with the drill again, boom, after 5 second oil started coming out of the top. So obviously the old pump worked.
When I did my rear main seal, I wanted to change the dented pickup tube. The pickup tube has a bracket on it that overlaps one of the pump's mounting bolt holes. To try and change the pickup, I removed that bolt. I started yanking on the pickup tube to try and remove it and decided to abort the mission, as I didn't know how hard it would be for me to press in a new pickup tube after the fact. I put the bolt back and forgot about that idea. Fast forward to now, after discovering the hole in the pump that has to be plugged, I wondered if maybe me removing the oil pump bolt in the past ruined that gasket and now the hole wasn't plugging properly, hence no suction?? You can see the bulge where the empty hole pressed against the gasket, so I was wondering if me removing that right side bolt for the pickup tube and then reinstalling possibly screwed up the gasket sealing with that hole, hence losing suction.
So, I ordered a new pump, pickup tube, and gasket. With all of this I figured new parts are best. I tested the old pump in some nasty oil too, so getting a nice new clean part to work with seemed like a good idea. Today I got all the parts:
Melling M81A Oil Pump
Melling 242S pickup tube
Melling MCAT-62 install tool (highly recommended!!!!!)
Fel Pro Oil Pan Gasket
6 more quarts of stupid oil after I just wasted the last 6 quarts
Nice new pump and pickup tube pressed together...
I pressed in the pickup tube and went to install. Everything went right on. I went to crank the engine with the starter again, with the pickup tube dipped in oil. Lo and behold.......still no freakin' oil pressure. After nearly yanking all my hair and setting the Jeep on fire, I decided to sit and think. The only thing I hadn't done yet was truly prime the engine with a drill, flat blade screwdriver, and do it through the distributor hole. I didn't want to but I decided to pull the distributor and go to harbor freight for some screwdrivers that I could chop up and stick in my drill. I got this bad boy stuck in the drill and did some pumping.
After something like THREE minutes, I FINALLY got oil pressure. I was monitoring the oil through the filter spot. I removed the filter. The oil gets pumped to the filter first, so as soon as oil came out of the filter hole I knew. Then I put the filter back on, put the oil pan, starter, etc on. I filled the oil pan up with 6 quarts of oil and did a crank with the starter. Finally, some damn oil pressure when cranking! I could have sped this process up by packing the oil pump with vaseline, but I didn't want to open up the brand new pump because it has a gasket in it that I didn't want to mess up and then introduce more questionable areas of possible failure.
Pic of the oil pump that you "spin" with the drill from above. You stick the flathead screwdriver into here and run the drill clockwise, simulating the job the distributor usually does.
I buttoned back up all the ignition stuff, ASD relay, fuel relay, etc. I gave it a quick prayer and started it up. 50 PSI oil pressure!! It sounded great and was idling smooth as a YJ engine can.
So the moral of the story here is that it wasn't any of the millions of things I checked. It was seriously that the system was empty and needed priming, and all the starter usage was too fast to actually begin sucking up oil. What I should have done from the beginning was pull the distributor, spin the pump with my drill and screwdriver, and I would have built up pressure and never had to change the pump, dropped the pan, etc. Oh well, you live and you learn.
Really, there are two morals. The first moral is to run your engine more often so this never happens. The second moral is to check and try truly priming the oil pump in case the system ran dry. Had I done all that to begin with, life would have been a lot easier. The better plan though is to run the engine often enough so the system doesn't go dry.
I finally got my new Mopar spark plug wires too so I went ahead and installed them today after the engine was running properly again. What a damn mess. At least I know I have a good oil pump and pickup tube now!
Thanks @SirDoopYJ and @jeepjoe43 for letting me vent a small bit while I worked through the process trying to figure it all out lol.
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