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No oil pressure when cranking - 6.0L

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Old 02-16-2011, 09:55 AM
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Default No oil pressure when cranking - 6.0L

Ok, so with my swap, I finally got oil in the engine, took out the plugs and tried cranking over the motor. I wanted to do this so I could prime the engine with oil.

The worst case scenario is happening, where oil is not being picked up at all. I made sure the oil level is up and still nothing. I pulled the lines on my oil filter and it's not even making it to the filter. I know cranking isn't fast enough for getting full pressure, but shouldn't I get SOME oil flow?

What could cause this? Would it be the oil pump? Could it be a pickup tube? It does have a modified pickup tube, but it extends deep enough into the pan, where it's submerged in the oil right now. I was really careful not to pinch the o-ring when I put the pickup tube on. But can I check that by pulling the front cover? Is there enough access when you do that, or do I have to pull the motor?

I'm fearing that I have to pull the motor, which is about the worst thing I could think of doing at this point. I can't get to the oilpan because the front diff is in the way.

Anyone have any suggestions to check?

It's an LQ4, stock internals, custom oilpan and pickup tube.

Thanks,
Old 02-16-2011, 11:59 AM
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Did you verify this with a mechanical gauge?
Old 02-16-2011, 02:09 PM
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Well here is the process that I went through:

Cranked the motor for 10-20 seconds with the spark plugs removed.

Removed the oil filter......saw that it was bone dry.

Replaced the filter, and took off the front galley plug (front driver's side of the block)

Cranked the motor for another 20'ish seconds and nothing came out.

I'm going to remove the front cover tonight and see if I can access the pickup tube enough to inspect the o-ring.

I've seen conflicting stories where cranking doesn't spin enough to get the oil flowing, and you actually have to get the motor running for 2-5 seconds before you get oil pressure. But then again, I've seen others say that you should get SOME oil flow from cranking, but not close to normal oil pressure (~5psi).
Old 02-16-2011, 02:23 PM
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Originally Posted by PPI Typhoon
Well here is the process that I went through:

Cranked the motor for 10-20 seconds with the spark plugs removed.

Removed the oil filter......saw that it was bone dry.

Replaced the filter, and took off the front galley plug (front driver's side of the block)

Cranked the motor for another 20'ish seconds and nothing came out.

I'm going to remove the front cover tonight and see if I can access the pickup tube enough to inspect the o-ring.

I've seen conflicting stories where cranking doesn't spin enough to get the oil flowing, and you actually have to get the motor running for 2-5 seconds before you get oil pressure. But then again, I've seen others say that you should get SOME oil flow from cranking, but not close to normal oil pressure (~5psi).
I'm honestly not sure how much oil pressure the GENIII engines make while cranking, but as long as the oil pump is turning, it should circulate some oil (I assume, don't take that as fact), unless maybe the pressure relief valve was stuck or something.

What's custom about the oil pump pickup and pan, got any pics?
Old 02-16-2011, 02:39 PM
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should make somethign while cranking i do this after my truck sits for a long time to prime it (pull the fuel pump relay before cranking) and it should make at least 20 ish psi on a stock motor.

problems could be , pinched or damaged pickup o ring allowing it to suck air or something is internaly damaged in the motor not allowing oil flow passed a certain bearing or blockage in the block.
Old 02-16-2011, 04:08 PM
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Originally Posted by budhayes3
I'm honestly not sure how much oil pressure the GENIII engines make while cranking, but as long as the oil pump is turning, it should circulate some oil (I assume, don't take that as fact), unless maybe the pressure relief valve was stuck or something.

What's custom about the oil pump pickup and pan, got any pics?
Well here is the pickup:



The pan is this:




I'm pretty sure I must have done something to the o-ring. Can't I get to the o-ring by taking off the front engine cover?
Old 02-16-2011, 04:10 PM
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Originally Posted by 2004SSS
should make somethign while cranking i do this after my truck sits for a long time to prime it (pull the fuel pump relay before cranking) and it should make at least 20 ish psi on a stock motor.

problems could be , pinched or damaged pickup o ring allowing it to suck air or something is internaly damaged in the motor not allowing oil flow passed a certain bearing or blockage in the block.
Yeah I have a pressure pot I was thinking of draining a few quarts of oil, put it in the pressure pot, pressurize the pot up to 50'ish psi and push it through the system to check for flow.

Going to see what I can come up with tonight and I'll post back.


Thank you everyone for the help.
Old 02-16-2011, 04:21 PM
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you might have to drop the front of your oil pan to get to the O ring
Old 02-16-2011, 04:32 PM
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Originally Posted by blazinblue
you might have to drop the front of your oil pan to get to the O ring
Yeah I was afraid of that.

You can see the diff doesn't allow me to get to a few of the bolts.



I guess I could try to lift the engine up a few inches so I can get to the blocked bolts and see if I can do it that way.

Thanks
Old 02-16-2011, 04:33 PM
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Did you check clearence from the bottom of the pickup tube to the floor of the oil pan? You need at leas 1/4-3/8" of clearence, but I like having 1/2".


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