Symptoms of a failing oil pump?

Discussion in 'Fox 5.0 Mustang Tech' started by Black Sun 5.0, Jun 30, 2008.


  1. Black Sun 5.0

    Black Sun 5.0 Founding Member

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    The title says it all. Thanks.
     
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  2. ShortThrow50

    ShortThrow50 Member

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    low pressure. no pressure. noisy pump
     
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  3. Black Sun 5.0

    Black Sun 5.0 Founding Member

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    Definition of noisy? Squeaks/squeals on start, perhaps?
     
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  4. ShortThrow50

    ShortThrow50 Member

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    you shouldnt be able to hear your oil pump at all. carefull what your listening too though. in the past i have misdiagnosed oil pump noise with something else. also, i have only has one oil pump go bad and that was on an old ass truck thatwas losing pressure and i only assume the rest from other readings that turned ot to be bad pumps. give this thread a coupl more hours and im sure some other bad oil pump victims will chime inthis tread to help out
     
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  5. LiquidGT

    LiquidGT Member

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    Used to have a Tempo a long time ago, the motor sounded fine then the oil pump just went out while on the highway.


    Are you going by the factory OP gauge?
     
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  6. Black Sun 5.0

    Black Sun 5.0 Founding Member

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    I'm still on the factory gauge, but it just started dipping.
     
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  7. LiquidGT

    LiquidGT Member

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    Before you give any more concern, change the sending unit, its only $10-20 bucks.

    Or you could get one of those mechanical Sunpro gauges from AZ for $20 and put it on the cowl vent temporarily.
     
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  8. Bullitt95

    Bullitt95 Active Member

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    Noise from a failing oil pump is almost unheard of. It's water pumps that'll often make noise when they're failing. The following are more common signs of oil pump failure:

    1. Steady decrease in oil pressure over time. Usually the result of gradual oil pump wear where oil pressure will be low at idle and at higher rpm. May also be accompanied by rod/main bearing wear.
    2. Fluctuating oil pressure. Most common reason for a truly fluctuating oil pressure is a sticking oil pressure relief valve, but a fluctuating dashboard gauge is almost always caused by a bad sending unit that's sending false information to the gauge.
    3. Sudden loss of oil pressure. Almost always the result of a broken or twisted oil pump shaft.

    If you have a low oil pressure at idle but at least 40psi from 2000rpm upwards, the most likely cause is worn rod/main bearings. If an oil pump can generate at least 40psi of oil pressure from 2000rpm upwards it's definitely still good.
     
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  9. Black Sun 5.0

    Black Sun 5.0 Founding Member

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    FYI: When I rev the engine or drive at higher rpms, the gauge does not indicate higher pressure. Also, how can one tell if the bearings are worn. What totally sucks is the fact that this engine only has 13,000 on it, but other issues with the car could have resulted in damage. Thanks.
     
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  10. Black Sun 5.0

    Black Sun 5.0 Founding Member

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  11. Bullitt95

    Bullitt95 Active Member

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    Verify your oil pressure readings with a mechanical oil pressure gauge. If they're normal, it's likely your factory oil pressure gauge sending unit is bad. If they're low even when you rev the engine up, the most likely reason is either a worn oil pump or an oil pressure relief valve that's stuck partially open. In both cases you'll need a new oil pump.
     
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  12. Black Sun 5.0

    Black Sun 5.0 Founding Member

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    Sounds good, thanks.
     
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