Need some help with understanding oil pressure | FerrariChat

Need some help with understanding oil pressure

Discussion in '348/355' started by Shootfighter65, Jun 24, 2015.

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  1. Shootfighter65

    Shootfighter65 Formula 3

    May 13, 2014
    1,372
    Charleston SC
    Full Name:
    Randy..alluneedtokno
    My 97 355 is running great. Thing is we moved to SC and the car was delivered yesterday. After a quick drive on the way back it seemed like my oil pressure was low. I looked in the reservoir and there was no oil in it Kinda freaked me out but checked the oil and it's just below max. Running it around it seems oil pressure is lower than normal. At 3000 rpm it's just above the 70 mark. But at idle it seems to drop alarmingly low. Down around the second mark. In Mochigan it seemed to always idle just below the 70 mark. Oil temp is around 210 like normal water around 190. The oil pressure dropping so low at idle concerns me along with not seeing oil in reservoir. I have checked the oil hot,cold,running,engine off. Always right below max. Maybe I am doing something wrong. Sorry typing on my iPhone. Anyone have some input?
     
  2. 8500rpm

    8500rpm Formula Junior

    May 20, 2014
    546
    San Francisco Bay
    Full Name:
    Chan
    In California my oil pressure drops to around the 2nd mark when warm and idling. It rises with throttle application. At cold start it pegs at the 1st mark above 70 psi then gradually falls at the car warms up.
     
  3. Shootfighter65

    Shootfighter65 Formula 3

    May 13, 2014
    1,372
    Charleston SC
    Full Name:
    Randy..alluneedtokno
    That low mark is what worried me. It used to idle around the 70 mark
     
  4. Eric C

    Eric C F1 World Champ
    BANNED

    Mar 20, 2009
    11,136
    St. Louis, MO
    Full Name:
    Eric
    When hot, mine sits at the 2nd mark at idle.
     
  5. kenneyd

    kenneyd Formula 3

    Sep 30, 2014
    2,027
    NE FL
    Full Name:
    Ken
    I pretty sure the owners manual states this is normal, and it is consistent with my experience.
     
  6. RWP137

    RWP137 Formula 3

    Apr 29, 2013
    1,611
    AZ
    Full Name:
    Rick
    Sounds normal to me. Best to check the oil level while car is hot and running and you really won't see any oil when looking in the reservoir.
     
  7. Shootfighter65

    Shootfighter65 Formula 3

    May 13, 2014
    1,372
    Charleston SC
    Full Name:
    Randy..alluneedtokno
    Eric I trust what you say. Doesn't that worrie you?
     
  8. plugzit

    plugzit F1 Veteran
    Silver Subscribed

    Dec 1, 2004
    7,785
    Redondo Beach, CA
    Full Name:
    Bruce Bogart
    Normal. 10psi/1000rpm max 70ish is considered adequate pressure.
    Check your manual.
    Much more than 70 is cause for alarm, indicating either a bad spring in the pump bypass valve or a dying pressure sensor.
     
  9. andrew911

    andrew911 F1 Rookie
    Silver Subscribed

    Sep 8, 2003
    2,894
    Northern NJ
    How is there no oil in your reservoir but it reads close to max? Contradictory statement?

    You may have not noticed it before but the oil pressure does drop as the oil warms up and the oil gets thinner. As long as you have oil between max and min with the motor fully warmed up and measured on flat surface with motor running (dry sump so keep it on - the manual says you can also check it right after turning the car off but I leave it at idle) you should be good. Don't be tempted to put more oil in unless it needs it- there is a difference in level with the oil temp barely off he cold peg vs being at or close to the 12 o'clock position- common for people to put to max line when measuring with colder oil which leads to an overfill... I always aim for between max and min at full operating temp to try to avoid overfilling.
     
  10. greyboxer

    greyboxer F1 World Champ

    Dec 8, 2004
    12,689
    South East
    Full Name:
    Jimmie
    You've moved further South so isn't the ambient temperature higher (certainly than when you last drove your car) ? Maybe the oil is thinner as a result
     
  11. andrew911

    andrew911 F1 Rookie
    Silver Subscribed

    Sep 8, 2003
    2,894
    Northern NJ
    #11 andrew911, Jun 25, 2015
    Last edited: Jun 25, 2015
    By the way, I didn't mean to sound sarcastic in my post about you "not noticing it before"- I just meant it literally. I say that since the other day I thought my oil pressure looked high at fast highway speeds and I was trying to recall where it was in my prior 360 (similar motor) at a similar speed- I honestly can't recall so then I though it may be normal that I just never thought about it? The 355 motor revs a little higher than the 360 at say 80-90mph- I think it's up to or over 4,000 rpm at that speed, so I guess that's relatively fast turning and the pressure should be relatively high.

    Now I'm curious- what pressure do people typically see at say 80 mph?

    To your original question Shootfighter, with a fully warm motor oil- 210 or so- the oil pressure is very low on the gauge at idle and lower rpms. It would be higher if the motor wasn't warmed up yet, especailly for the first few minutes. It sounds like your car is fine to me...
     
  12. Enzojr

    Enzojr F1 World Champ

    Dec 12, 2013
    14,001
    West of PDX
    Full Name:
    Tomy
    Mine does this, and I just had a new oil pressure sending unit installed and also had them check the pressure mechanically... all good.
    Pressure up at start, then drops .... Under load up around the 90, idle at a light down to that second mark on the left.
     
  13. Eric C

    Eric C F1 World Champ
    BANNED

    Mar 20, 2009
    11,136
    St. Louis, MO
    Full Name:
    Eric
    I was thinking about replacing my sending unit, but if yours stayed the same, then I guess why bother?

    Here's some more chit chat about this topic, including the oil light flickering on and off.

    F355 oil pressure issues - PistonHeads
     
  14. Enzojr

    Enzojr F1 World Champ

    Dec 12, 2013
    14,001
    West of PDX
    Full Name:
    Tomy
    Oops forgot to mention that before I changed it out it was almost pegged at the 130 mark.
    Just looked down while driving and thought OH SH**, that looks expensive .... but the sending unit and new rubber boot was reasonable.
     

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