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oil pressure problem

Discussion in 'Ford Trucks' started by Lucfw, May 18, 2013.

  1. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    I got a 1997 f150 4.2 v6, its just my daily driver not really a work truck and when im driving the oil gauge is fine but after driving it for a while, when its warm and i come to a stop the oil pressure gauge starts to go up and down.
    It only does it when its warm.
    When no throtle is applied.
    There is no noise coming from the motor that should not be there.
    Im just wondering what it could be? I read about the sending unit and stuff but i dont think its that, So im just wondering if its somthing i should be watching or if its just something thats nothing to worrie about.
    Thanks
     
  2. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    How many miles on it? Change oil filter lately? Could be clogged and the bypass is kicking in.
     
  3. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    there is 364 xxx KMS on it, but the sensor that does the odometer is jumping and changes at differnt paces.
    I did just do a oil change in the fall, it should get one done soon. I put lucas oil stop leak in there to help with a oil leak.
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,963

    well only real way to rule out anything is put a gauge on it and see if it jives with the dash gauge
    why do you not think its the sending unit??
    if your speedo is jumping as well as gauge,,,,might be cluster related
     
  5. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    My speedometer got stuck at 0 a couple times, slap the glass infront and it will work.

    How do you put a differnt gauge on to read the pressure? like is it kinda plug and play to get a more accurate reading?
    I thought if it was the oil sending unit i would have the problem all the time. I could be wroung.
    Thanks for your help guy.
     
  6. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Most times the dash gage does not have a problem. If it really bothers you change the sending unit on the engine. How much does in move? Big swings or you just see it move a little? What is the MILES on it? I am a dumb American I don't know your measure of distance.
     
  7. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,963

    You have to put on a testing gauge...mechanical screw in gauge. Used just for testing
    What if the internals of the sending unit are on the fritz and only act up when they get hot ?
     
  8. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    226.1791 miles, i belive, i m bad at conversions.
    It does not bother me, i just what to make sure its nothing major. Its normaly in the middle of the gauge then when i stop it moves up to about 3 1/4 up and down to just above the red., i think once it went to the red.
    But when its doing this the engine runs fine, no nosies or anything.
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,963

    Is prob say sending unit. But get it tested
     
  10. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    Ok, so testing it would it be something i can do at home? (if i get the mechanical gauge)
    THanks for your help guys. Ive never done much with the oil system, other than oil change and seals.
     
  11. fordrulz

    fordrulz Junior Member
    Messages: 18

    You need to remove the sending unit near the oil filter and install a manual guage
    in it's place than check the pressure when the engine is hot. Good luck!
     
  12. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    oh i see. ok, seams like somthing that if you screw up your getting burnt. lol
    So if i dont replace it what could happen? like one day it just stops then no oil pressure? or will it give me notice.
     
  13. fordrulz

    fordrulz Junior Member
    Messages: 18

    The oil pressure switch just lets you know if there is oil pressure but does not tell you how many psi. So if it is just a faulty sending unit and the oil pressure is actually ok there will be no issue other than a inop guage.replacing the sending unit is a easy fix though
     
  14. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    ok thanks, next oil change ill replace the sending unit. ill let yall know if it works.
    Thanks so much for all your help!
     
  15. damian

    damian Senior Member
    Messages: 330

    just so you know the oil pressure guage on that truck is not really a guage,it is either reading zero or normal. it is operated by a switch,i believe over 8 psi switches on,under that and you get zero. that is why no ford truck past 1996 i believe will ever have a variable reading guage when accelerating or decelerating, cold or hot,they read either zero or normal. you may have a bum sender switch but you need to hook up a live guage to be sure.
     
  16. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    I new about the gauge before it gave me problems, thanks anyway damian.

    So i did a oil change, i did not put the lucas oil stop leak in. I have the oil pressure sending switch but i could not get the old one out. it was so close to the oil filter head i could not even get a socket or a wrench (box or open) on there. also it looked really rusted, i did not want to strip it.

    So after driving it around it seems like the pressure gauge is worse. But again no nosie from the engine.
     
  17. fordrulz

    fordrulz Junior Member
    Messages: 18

    There is a special socket to fit the sending unit... Why not right can't be easy! Sounds like that is defiantly the problem though if there is no engine nose. Good luck!
     
  18. Lucfw

    Lucfw Senior Member
    from Ontario
    Messages: 307

    ya thats what i thoght. next time there on sale at princess auto ill pick them up.
    Stuiped question, i think i know the answer, can you change the switch with out drain the oil? I dont think so but i could be wroung.
     
  19. fordrulz

    fordrulz Junior Member
    Messages: 18

    There is a special socket to fit the sending unit... Why not right can't be easy! Sounds like that is defiantly the problem though if there is no engine nose. Good luck!
     
  20. fordrulz

    fordrulz Junior Member
    Messages: 18

    No need to drain the oil you will only loose a small amount when removing the switch.