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Thread: wheres the oil pressure?

  1. #1
    Join Date
    Feb 2010
    Location
    Odessa, texas
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    wheres the oil pressure?

    just rebuilt a lq4 and it wont make more that 20 pounds at idle and when it warms up its about 7 pounds ive changed the seal and the oil pump and nothing

    any advice?

  2. #2
    Join Date
    Nov 2003
    Location
    Denton Texas
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    20,540
    Replace the cam thrust plate if the seal is damaged or warped. Another thing I've started doing is putting a bead of silicone around the pickup tube between the oring and the swedged metal bead. Be sure to let the silicone set up for at least two hours before starting the engine so the silicone has time to harden a little.
    Last edited by RedHeartbeat; 02-02-2010 at 08:22 PM.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  3. #3
    Join Date
    Nov 2007
    Location
    Pittsburgh, PA
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    3,581
    thats a loaded question. can be so many variables. wrong cam bearings, wrong main bearings, bad O ring, pump not sealing to block, oil passages clogged
    2002 Lightning - GT headed 5.5Litre w/ Twin 7665s
    2002 Silverado - 427Lsx w/ Twin gt4202s
    2010 Silverado crewcab Z71 - 5.3litre w/ procharger
    2000 Wrangler - 5.3litre with some stance
    2014 Xsport- 3.5 Eco boost
    412 Motorsports

    it ain't that I'm too big to listen to the rumors, It's just that I'm too damn big to pay attention to 'em..That's the difference

  4. #4
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
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    Dont forget the "forgot to install the dogbone" into the oil galley at the back of the engine.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  5. #5
    Join Date
    Feb 2010
    Location
    Odessa, texas
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    i used gasket sealer on the oring and the cam bearing and rod bearings are brand. new cam bearings are from the dealership. the thrust plate stayed in a box the entire time the motor was apart.never plled the dogbone out of the motor. when i changed the seal the second time(with the motor in the truck) i had to clean a lot of gunk out of the pickup tube. im think maybe the oil prssure sending unit might be clogged so im about to pull it out and check it

  6. #6
    Join Date
    Nov 2007
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    Pittsburgh, PA
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    Quote Originally Posted by danger_ranger83 View Post
    i used gasket sealer on the oring and the cam bearing and rod bearings are brand. new cam bearings are from the dealership. the thrust plate stayed in a box the entire time the motor was apart.never plled the dogbone out of the motor. when i changed the seal the second time(with the motor in the truck) i had to clean a lot of gunk out of the pickup tube. im think maybe the oil prssure sending unit might be clogged so im about to pull it out and check it
    new bearings dont mean anything if they arent properly matched to the crank. a polished or cut crank needs over sized bearings. if you didnt have this done to crank are you sure the crank didnt need checked?

    the sensor is reading so i woudl rule the sensor out
    2002 Lightning - GT headed 5.5Litre w/ Twin 7665s
    2002 Silverado - 427Lsx w/ Twin gt4202s
    2010 Silverado crewcab Z71 - 5.3litre w/ procharger
    2000 Wrangler - 5.3litre with some stance
    2014 Xsport- 3.5 Eco boost
    412 Motorsports

    it ain't that I'm too big to listen to the rumors, It's just that I'm too damn big to pay attention to 'em..That's the difference

  7. #7
    Join Date
    Feb 2010
    Location
    Odessa, texas
    Posts
    916
    Quote Originally Posted by Quik View Post
    new bearings dont mean anything if they arent properly matched to the crank. a polished or cut crank needs over sized bearings. if you didnt have this done to crank are you sure the crank didnt need checked?

    the sensor is reading so i woudl rule the sensor out
    the rod bearings only got changed bc the motor blew a head gasket and the bearings didnt look good


    so there is NO way the sending unit could be the problem?

  8. #8
    Join Date
    Nov 2007
    Location
    Pittsburgh, PA
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    Quote Originally Posted by danger_ranger83 View Post
    the rod bearings only got changed bc the motor blew a head gasket and the bearings didnt look good


    so there is NO way the sending unit could be the problem?
    if the rod bearings didnt look good then the crank is tore up then. having poor tolerances with rod-crank bearings will also cause low oil psi
    2002 Lightning - GT headed 5.5Litre w/ Twin 7665s
    2002 Silverado - 427Lsx w/ Twin gt4202s
    2010 Silverado crewcab Z71 - 5.3litre w/ procharger
    2000 Wrangler - 5.3litre with some stance
    2014 Xsport- 3.5 Eco boost
    412 Motorsports

    it ain't that I'm too big to listen to the rumors, It's just that I'm too damn big to pay attention to 'em..That's the difference

  9. #9
    Join Date
    Feb 2010
    Location
    Odessa, texas
    Posts
    916
    Quote Originally Posted by Quik View Post
    if the rod bearings didnt look good then the crank is tore up then. having poor tolerances with rod-crank bearings will also cause low oil psi
    the rod bearings werent tore up they just had nasty spots where the water was sitting

  10. #10
    Even with a new o ring on the pick up, you can still put it in wrong and pinch the o ring. Do what i did and cut a little section out of the two pick up tube brackets so you can move it around and get the oring to sit right.

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