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No oil pressure when cranking - 6.0L

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Old 02-16-2011, 04:48 PM
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You'll probably be best off dropping the diff to give you clearance, getting to that o-ring with the engine in the truck is a PITA
Old 02-16-2011, 04:55 PM
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I'd just start it. You have a LONG pickup tube and these oil pumps not good at sucking with no prime at just cranking speed. If you don't have oil pressure after it starts and runs a few seconds, then look deeper into it. I'm sure its fine
Old 02-16-2011, 06:26 PM
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Originally Posted by Atomic
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".
Yeah it's down there quite a ways. That's the reason for the modified pickup tube is the depth of the sump.
Old 02-16-2011, 07:03 PM
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As long as this motor isn't bone dry (as in brand new, no assy lube or anything) you will be fine to start it for a few seconds.
Old 02-16-2011, 08:11 PM
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Im with the last couple guys. When I went through my LQ4 before it went into the truck, I cranked it over for about 30 seconds and there was no OP on the gauge. Ive yet to see the gauges work during cranking so Im assuming anyone that does it has a mechanical gauge. I started it and it shot right up to 50psi.

A couple things to check.. I dont know how far you took the motor down, but did you replace the oil gally dumbbell plug in the back of the block? Did you use the right O ring for the pickup (I almost learned this the hard way.. there IS a difference in pick ups for the red and blue O rings)?
Old 02-16-2011, 08:16 PM
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Originally Posted by kbracing96
I'd just start it. You have a LONG pickup tube and these oil pumps not good at sucking with no prime at just cranking speed. If you don't have oil pressure after it starts and runs a few seconds, then look deeper into it. I'm sure its fine
This would be my bet too. I have seen a couple motors go ahead and prime up with just cranking rpm but most of them take a couple of seconds of running before it will go ahead and bump on up.

If it doesnt prime after running Id pop the motor mounts loose, dropping the front diff sucks.
Old 02-16-2011, 10:02 PM
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Ok well I'm glad I didn't start it up. I decided to pull the front engine cover:



I'm assuming the oil pickup tube shouldn't be cocked like that.

It must be a clearance issue with the oilpan. That's the only reason I can think of why it's moved over like that.

Oh well.......now I need to figure out if I need to pull the motor or just pull the front diff so I can get to the oilpan bolts, pull the oilpan and hopefully fix it with the engine in the truck.

Bummer.
Old 02-16-2011, 11:15 PM
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Glad you found the problem, now you just have to figure out the fix
Old 02-18-2011, 12:12 PM
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Well upon investigation, I found that the "custom" oil pickup wasn't custom enough.

Here is the reason for the bad fitting:



You can see that it hits the windage tray, so when you bolt the support down on the other end, it "rocks" it to one side, causing the problem.

Here it is after a little "massaging"



Now I get to wrestle the motor back into place.
Old 02-18-2011, 12:42 PM
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i had a feeling it had something to do with the oilpan i didnt even notice it had a custom one until i saw it and re-read.

i know on my truck i say oil pressure when cranking , let us know if you get it when you try and prime before initial start. sucks you had to pull it though .


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