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Oil pressure fluctuation?

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Old 12-01-2007, 01:48 PM
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Default Oil pressure fluctuation?

I got an 00 ls1 with 72000 on it, when I start it up in the morning the oil pressure is about 65-70, after it warms up it stays around 60psi but, after a long drive or idling for a long time the oil pressure drops to 40psi and doesnt move from there even under a load. It doesnt bother me when Im idling and its at 40psi but when I go and take the motor to 2500rpm or up it barely goes past 40psi. Anyone got any ideas? Im using castrol full synthetic oil. I really hoping that my main or rod bearings arent trashed.
Old 12-01-2007, 01:54 PM
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It would not be a bad idea to start with the sending unit. They do seem to fluctuate with age. I replaced mine when I broke it removing the intake a while back. Before I replaced it oil pressure sat around 35 at idle and with the new one it was around 45. It now has settled to about 40 at idle but it does move when I give it gas. It is pretty easy to change with the intake off but I belive it can be done with the intake on. Buy the socket to remove it and it should be pain free.
Old 12-01-2007, 06:10 PM
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Originally Posted by THE CHOP SHOP
It would not be a bad idea to start with the sending unit. They do seem to fluctuate with age. I replaced mine when I broke it removing the intake a while back. Before I replaced it oil pressure sat around 35 at idle and with the new one it was around 45. It now has settled to about 40 at idle but it does move when I give it gas. It is pretty easy to change with the intake off but I belive it can be done with the intake on. Buy the socket to remove it and it should be pain free.
Cool Ill try that tommorow, I hope thats it (fingers crossed) Is it a special socket that removes the oil pressure sender?
Old 12-01-2007, 06:12 PM
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Originally Posted by allthrotle
Is it a special socket that removes the oil pressure sender?
Yes, you can buy it at just about any parts store.
Old 12-01-2007, 06:52 PM
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Yeah there are a couple different specialty sockets out there. You will need the deep one because of the length of our sending unit. If you buy the new sender just go look on the tool shelf and you should be able to find one that will work.
Old 12-08-2007, 05:05 PM
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Did you ever figure out the problem???
Old 12-08-2007, 05:27 PM
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i have seen pressure springs in oil pumps fatigue with age and they show their *** on a warm or hot motor. great pressure while its cool, then **** later. i had one go from 60 at cold idle to 10 or less at warm idle and the motor would start to tremble. i got one from autozone, it shot to 70 at cold idle and never, never drops below 35. pretty good for a POS DD and only spending $40
Old 12-08-2007, 05:38 PM
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^Ya it could be that spring, cause thats what its doing on me. Still havent figured it out yet and Im a little broke to buy a new oil pump. I havent replaced the sender yet either. I'll replace both when I get paid next week.
Old 12-08-2007, 05:59 PM
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Mine has been gradually going down. I dont have any knocking or anything like that, its just going down. Now im at 18psi at hot idle and anywhere from 30-38psi on a cold start. Its starting to worry me. Im gonna replace my oil pan gasket and my oring while im in there. Hopefully this will cure some of the problem. What do you all think??
Old 12-08-2007, 08:13 PM
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Originally Posted by blkbird
Mine has been gradually going down. I dont have any knocking or anything like that, its just going down. Now im at 18psi at hot idle and anywhere from 30-38psi on a cold start. Its starting to worry me. Im gonna replace my oil pan gasket and my oring while im in there. Hopefully this will cure some of the problem. What do you all think??
Damn thats alot worse then me, so I hope if you change out your pump and spring it would fix it. Ill swap my pump out when I change heads and cam.
Old 12-08-2007, 11:38 PM
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when you put the new pump in there its gonna rock yo world. That needle is gonna be crying for help...
Old 12-09-2007, 07:32 AM
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I replaced my oil pump when i did my cam two years ago.....



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