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328 High Oil Pressure

Discussion in 'Technical Q&A' started by btemplin, Dec 14, 2004.

  1. btemplin

    btemplin Rookie

    Dec 17, 2003
    39
    Houston, TX
    Full Name:
    Brian Templin
    My '86 328 has had a steady increase in oil pressure over the last few weeks. When I purchased it 6 months ago, the oil pressure was pretty consistant around 85 psi. The previous service for the car used 20W-50 dino oil. Since then I've put ~4000 miles on the car. In recent weeks, the pressure has risen to ~130 psi. Just above when driving, just below at idle.

    Last night I changed the oil & filter for the first time. I used Mobil 1 5W-30. The previous filter was Baldwin, and that is what I used this time. While test driving after the oil change, the pressure was still around 130.

    There are 36,000 miles on the car.

    Any thoughts on possible causes / problems?

    Thanks,
    Brian
     
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  3. jimangle

    jimangle Formula 3

    Nov 5, 2003
    2,442
    Haverford
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    James
    Btemplin,
    Maybe the gauge is faulty? 130 is really high. I'd take it to a dealer.
     
  4. flyingboa

    flyingboa Formula 3

    Nov 27, 2003
    1,555
    Italy/India
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    Eugenio
    I had the same problem with my car. Everything was sorted applying service bulletin No 16-2, whose description is:

    A new spring for oil pressure relief valve (P/N 133550, Spare PartCatalogue Tav 21, Item 27) has been introduced; the new spring is more flexible and slightly shorter than the spring previously used.

    Oil pressure is now within limits.
    Ciao
    Eugenio
     
  5. rimoore

    rimoore Formula 3

    Nov 18, 2004
    1,285
    Island in Maine
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    Richard Moore
    On my 308 you can connect an external guage right where the oil filter goes. I had the opposite problem with a low pressure guage. The manual check verified all was well.

    Rick
     
  6. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,415
    USA
    Brian,
    There was a Technical Service Bulletin specific to this issue on early 328's.

    Go here: http://bingo.cdyn.com/ferrari/328_bulletins.pdf

    See under "service bulletin Index" and find #16-2, dated 06/05/87

    My car (1987, built after the change in spring), was reading over 120 psi all the time. I am guessing that something is changing in the spring from age or heat, resulting in the change in oil pressure. My independant Ferrari technician connected a mechanical guage to verify the pressures (he found my guage pretty close, reading maybe 5psi high). He then swapped out the spring to get the max. pressure to bleed off at around low to mid 90 psi, where it is supposed to.
     
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  8. GrigioGuy

    GrigioGuy Splenda Daddy
    Global Moderator Owner

    Nov 26, 2001
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    Brandon Lesco
    I'll echo Eugenio's comments -- I also had high oil pressure on my 87 328, and the new spring lowered the maximum pressure. You should probably have this done.

    Howeverm it sounds as if your gauge is not reading correctly. Try attaching a mechanical gauge and see what it reads.
     
  9. bpu699

    bpu699 F1 World Champ
    Silver Subscribed Owner

    Dec 9, 2003
    13,597
    wisconsin/chicago
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    bo
    Get an oil pressure gauge at pep-boys and check the pressure manually at the sending unit- hopefully your gauge is broken. Otherwise your oil pop-off valve is stuck. Or at least thats what it would be if it were a 911 - my only previous experience.

    Good luck!
     
  10. jaturon

    jaturon Formula 3

    Oct 25, 2004
    1,599
    Bangkok Thailand
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    Zane
    My advice is to take it to the mechanics and let them see as high oil pressure is pretty critical. It might be the fault of the gauge nothing else but better be safe.
     
  11. btemplin

    btemplin Rookie

    Dec 17, 2003
    39
    Houston, TX
    Full Name:
    Brian Templin
    Thanks for the information so far. Very helpful!

    Now, where on the car will I find the oil pressure relief valve, and the oil pressure sending unit?

    Brian
     
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  13. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    The oil sending unit is at the base of the oil filter.
    The valve is at the front of the motor next to the crank pulley on the left side. It is the large cad plated cap plug.

    Be very careful running that motor until you have it sorted out. You are very close to the pressure it takes to blow oil lines and coolers. It happened to many 86 3.2's until we lowered the pressure.
     
  14. btemplin

    btemplin Rookie

    Dec 17, 2003
    39
    Houston, TX
    Full Name:
    Brian Templin
    Is it safe to assume that I'll need to drain the oil in order to remove the pressure relief valve and change the spring?
    Is there anything else I'll need to disassemble / remove to get to the valve??
     
  15. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,489
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    No need to drain oil, just let car sit with motor off overnight if poss before removing.

    Under the cap will be a spring (remove cap carefully) a tiddly wink spacer and a piston. If your car is below #63809 make sure it has a piston with 3 holes in it. I was supposed to be replaced in recall #143. Make sure piston slides free full length of bore.
     
  16. btemplin

    btemplin Rookie

    Dec 17, 2003
    39
    Houston, TX
    Full Name:
    Brian Templin
    #13 btemplin, Dec 19, 2004
    Last edited by a moderator: Sep 7, 2017
    Is this the cap you are referring to?
    Just for the heck of it, I put a wrench on it earlier, and found it to be on very tight. From the position I was in, I didn't have much leverage, but I could not break it loose. Will have to find a way to get to it where I can put some force on the ratchet. Any thought as to what this should be torqued to?
    Image Unavailable, Please Login
     
  17. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,489
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    Brian Crall

    That's it. I reread the recall and found no torque spec, use your judgement. Just remember you can tighten it more if it seeps a little but you can't unstrip the aluminum.
     
  18. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    I had mine off a few times and it really takes some force to get off.
    Just tighten the cap nut "a lot"
    When you at it consider changing the copper wasker as well - an incorrect thickness can influence the oil pressure somewhat
     
  19. btemplin

    btemplin Rookie

    Dec 17, 2003
    39
    Houston, TX
    Full Name:
    Brian Templin
    I changed the spring today. The new spring is a few millimeters shorter than the one I took out of the car.
    By "piston", I assume you are referring to the hollow cylinder that houses the spring. I pulled it out along with the spring. It does not have holes of any kind in it. My serial# is 64711.
    Now the oil pressure is running around 85psi at idle, and 105psi at speed.

    I found out something interesting today that I had not noticed before. It appears as though all of my previous gauge readings were incorrect. I always drive with my lights on. Even during the day, I turn on my fog lights. Today while test driving after changing the spring, I had my lights off for a bit, then turned them on. When I did, all my gauge readings (oil temp & press, water temp) jumped up a little bit. The 85 & 105 readings mentioned above are with the lights off. When I turn on the fog lights, the oil press goes to ~120psi at speed.

    So if the 85 & 105 readings are the true numbers, are those acceptable, or should I still be looking for another problem?
    Is my piston without holes a contributing factor?
     
  20. flyingboa

    flyingboa Formula 3

    Nov 27, 2003
    1,555
    Italy/India
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    Eugenio
    Just to clarify a point. My car, italian standard, has the Oil pressure indicated in Kg/cm2. By the books (i.e. Ferrari official workshop manual) the pressure normal operating value must be 4.5 at Idle and between 5.5 and 6.5 at 6000 rpm, the above with oil temp of 100 degrees Celsius.
    To the best of my knoweledge, that reads in a min pressure of 64 p.s.i. and a maximum one of 92.5 p.s.i. in warm oil conditions.
    Due to the above, your pressure seems to be too high anyway...
    When I replaced my spring, pressure went from too high to within the above normal ranges.
    I hope this was of help. Let me know how situation evolves.
    Ciao
    Eugenio
     
  21. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
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    THE Birdman
    If your guages read differently when the lights are on, either the battery or the alternator may be on the way out. The additonal load of the lights drops the voltage and changes the guage readings.

    Birdman
     
  22. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
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    Philip
    Sure sounds like a bad sender to me.
    Lots of good advice here.
    Philip
     
  23. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,415
    USA
    Depends on the accuracy of your gauge, but assuming it is close, that still seems too high. As stated, max pressure is supposed to be around 92psi according to the manual. Idle pressure should be around 45psi or so.

    Dave
     
  24. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,415
    USA
    Looking at the TSB again, looks like you need a couple more parts, the updated "plunger for control valve" and the "spacer for valve spring" #1-125885 and 1-131743 respectively.

    Refer to the recall on the "flexible oil lines".

    Dave
     
  25. KurtK328

    KurtK328 Formula Junior

    Mar 6, 2001
    347
    Villeneuve-Loubet, France
    Full Name:
    Kurt Kjelgaard
    It is quite normal for the gauges to show an increased reading when turning on the lights.
    I assume that the most correct reading is with the lights off since this the "normal" condition for driving.
    Numerous threads on this subject in the past.

    Nobody ever gave the final solution, (except of course to drive with the lights off) but the general consensus, as I remember, is that the grounding points for the instruments should be checked.

    And yes, you should change the piston as well to get the most up to date combination.
    Piston, spring and spacer in the cap nut under the spring should be the latest versions (125885, 133550 and 135679)
     
  26. blmjumper

    blmjumper Formula Junior

    Jun 18, 2006
    341
    Boise
    Full Name:
    Ty
    Is this a common reason for oil pressure to increase?

    I've been noticing a gradual increase over the last several months and it's getting to the point (or pressure) of worry.

    Several months ago, when the pressures began holding over 90 psi I noticed an abrupt drop (to what I would call normal, 45+/-)
    when I pulled in the driveway one day. That lead me away from a gauge problem or sending unit and more towards the spring.

    I'll be trying a mechanical gauge shortly just to eliminate a reading error on the dial.
     
  27. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
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    Paul

    There was a thread a year or so back, someone took the gauge sender apart to see what made it tick. You would be very surprized to see how crude it is.
     
  28. blmjumper

    blmjumper Formula Junior

    Jun 18, 2006
    341
    Boise
    Full Name:
    Ty
    Wish I'd read this a little better. Installed the new spring last night and although my oil pressure dropped a bit...not as much as it should. still in that 45-120 psi range as related to RPMs
     

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