Low oil presure

cumminspwr11

cumminspwr11

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May 18, 2010
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So I just got my Cummins build were I could drive it daily and I noticed after the oil gets hot my pressure drops to like 2 or 3 psi at idle. Any thoughts? I just did a complete rebuild, all the injector sprayers are installed oil pump worked perfect before the build, once I bring the rpms up the pressure builds right away
 
It's a 98 industrial Cummins block btw and I'm wondering if the 2nd oil feed line for the turbos has an effect on it??
 
Could be a freeze plug partially pushed out, relief valve stuck open, oil pump not seated into the block properly, suction tube overtightened and the gasket is split, wrong size rod and main bearings installed, or cam bearing not installed.

Normally, feeding 2 chargers will drop hot idle oil psi to 20 ish.
 
Yes I have a mechanical guage on it, the factory 6.0 gauge would just stay in the middle until I left off and it would drop to 0. I heard it works off a set psi of about 9 psi.

I watched it today from a cold start-20-25psi when first started, after it warms up on the freeway it runs about 9-10psi, dropping off to almost nothing at idle. I swapped the oil pump and have resealed the pick up, I had to have a cylinder sleeved so I'm wondering if a passage got block?? Maybe I can try moving the gauge to the port on the top of the filter and see what it says?
Also had to take the filter housing apart, is it possible I could have messed up the copper washer in the check ball spring assemble?
Pretty confident on the bearings being correct-I pulled the bearings and order replacements with the old part numbers, I compared the old bearings to the new ones before install, just trying everything I can before I pull the motor again
 
Oil pressure is pretty low all the time IMHO.

I never saw a 5.9L below 40psi above 1000rpm.

Sounds like big problems.
Chris
 
Ya I'm sure it is, this will be the third time pulling the damn motor, getting real tired of this lol
 
i know the cam bearing is in, just triple checked the old bearings, the connecting rod says STD on it, but I found a 0.25 on the main bearing, the number on it is 3929017 and when I crossed it it came back with a standard size bearing, can someone confirm this for me? Please
 
Also something just came to mind, if I used a storm block oil filter housing gasket in a non storm motor could that cause oil pressure issues?
 
Quickserve says that is a .25mm bearing. Yes, the wrong gasket in the filter housing can also cause low pressure. I forgot to mention that the first time around.
 
Did you have a machine shop measure your rod and main journals to determine e bearing sizes you should be using?
 
Looks like I'm gonna find out one way or the other, blew another head gasket-got the head resurfaced last time, now it's the blocks turn �� This has been the worst motor ever, someone left it out in the rain and ruin a cylinder that I had to get sleeved-the shopped that sleeved it was shotty, I would assume they would check the block after installing the new sleeve but I guess that's too much
 
Doesn't sound like the worst engine, sounds like the worst machine shop.

Can't do anything without a good machine shop.
Chris
 
That pressure is definitely low. Cold oil pressure is usually scary high if you're reading a gauge (60-100).
 
i don't use the shop that did the sleeve anymore, he broke three sleeves in my block and ended up putting in one that was 3/8" thick. I used a different shop for the head and that's where my block will be going now. when I told them what happened with my block the first time they told me that they had a block there that they fixing from that same guy.

no doubt its low, I did confirm that I used standard main bearings where the ones I pulled out were .25mm so I will be able to replace those with the right ones, also I wasn't sure on the oil cooler gasket because my kit was missing that one and non of the auto parts stores could find anything on it so I ordered one online and couldn't recall if it was storm or non storm.
 
cumminspwr11 said:
i don't use the shop that did the sleeve anymore, he broke three sleeves in my block and ended up putting in one that was 3/8" thick. I used a different shop for the head and that's where my block will be going now. when I told them what happened with my block the first time they told me that they had a block there that they fixing from that same guy.

no doubt its low, I did confirm that I used standard main bearings where the ones I pulled out were .25mm so I will be able to replace those with the right ones, also I wasn't sure on the oil cooler gasket because my kit was missing that one and non of the auto parts stores could find anything on it so I ordered one online and couldn't recall if it was storm or non storm.
Click to expand...

Getting correct bearings in it will fix the pressure issue if it isn't too late. Plastiguage is your friend.
 
Haven't had a chance to do anything with this yet but I have a question before I start tearing down, when the HG blew this time it just spit coolant in a steady stream from between the head and the block, should I do any short of diagnostics while it's still together? I made a few 60-70lbs runs without any issues but didn't go over 3k, the leak started after I wrapped it to 4K, could this having any affect on it other than the block not being straight? Such as high coolant pressures? I would think I would have blown a freeze plug or a radiator line before pushing thru the HG
 
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