308 Oil Pressure Reading

Discussion in 'Technical Q&A' started by Cooly0, May 17, 2004.

  1. Cooly0

    Cooly0 Karting

    Nov 2, 2003
    Full Name:
    My 308 '80 GTSi seems to have a problem I just replaced the oil on it from 20W 50 to 0W40 and no I get a pressure reading of 0 no below 0 but right on it and It does not change, at least I cant tell if it moves a very small amount. Any Ideas? I would assume a lightier pessure load with synthetic but not this much obviously. Could it be the gauge, since I have checked the Oil level.
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  3. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    Sounds like you need a new sender...there are many threads on testing and replacing...recommend you check the archives. Grounding the lead to it should tell you if the sender is bad.

  4. Dave

    Dave F1 Rookie

    Apr 15, 2001
    Little Rock
    Full Name:
    David Jones
    So then the gauge was reading fine,
    you changed the oil,
    now you have no oil pressure reading from the gauge,

    check filter,
    drain plug,
    oil at what level,
    sending unit wire,

    I would hope it is the sending unit
    and not a loss of oil pressure.
  5. Dr.T348

    Dr.T348 Formula 3

    Jan 8, 2004
    Chicago NW Burbs
    Full Name:
    Richard T.
    I went from 15w-50 to 0w-40 this year. I noticed no big change in oil pressure. I don't think its the oil change. Something else is wrong.

  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    Full Name:
    Steve Magnusson
    Cooly0 -- What is the other engine oil pressure measuring system doing? (i.e., when the analog gauge reads "0" is the red warning light on or off?)
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  8. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    Also, is this reading just at idle, or at higher revs too? I switched from 15W50 to 0W40 and get somewhat lower idle readings when hot.
  9. AEHaas

    AEHaas Formula 3

    May 9, 2003
    Osprey, Florida
    Full Name:
    Ali E. Haas
    With a hot engine the difference in oil pressure from a 50 to 40 wt oil would be at most 10 - 15 percent.

  10. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    Birmingham, AL
    Full Name:
    Same for me too. I just use the "0W" in the winter for the cold morning cold starts. It ran a little less the normal ( just left of straight down ) when up to temp then it would swing near 0 at idle.
  11. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    Roseburg, OR
    Full Name:
    Hans E. Hansen

    Early 308s often have oil pressure near '0' when idling. Going from 50 to 40 (or vice-versa) makes a BIG difference in idle pressure. Just off idle (say 1200rpm) brings things up to normal.
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  13. Wasco

    Wasco Formula Junior

    Dec 9, 2003
    Full Name:
    I dont think it has any thing to do with your choice of oil. I have changed my sender cuz of Lower pressures but it always ran at least 35 lbs at 4k RPMs then after new sender it went up about 10 lbs at hot temps. I suspect my guage is a little stressed as well as it act funny sometimes. But your choice of oil should only change pressure only several lbs not from 30 to Zero! I would not hesitate on changing sender!
  14. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    The Cold North
    Full Name:
    I have had bad UFI filters cause this problem. In fact just last week on a TR. Fired the car up, very little oil pressure. After testing the gauge, a replaced the filter with another one. Pressure went right back to normal. Bad oil filter. You maybe experiancing the same thing. This is not the first time this has happend to me.

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