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oil pressure drops after warmed up by fastblack
Started on: 05-21-2008 12:27 PM
Replies: 8
Last post by: fastblack on 05-21-2008 04:48 PM
fastblack
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Report this Post05-21-2008 12:27 PM Click Here to See the Profile for fastblackSend a Private Message to fastblackDirect Link to This Post
i'm finally getting around to getting my car fully road worthy (it's close). i drove it over to a friends house last weekend which is about 15 miles away. this is about the longest trip the car has had in a LONG time. oil pressure is fine when i start it, but by the time i got to my friend's house the oil pressure was VERY low (near the red on the gauge) when the car was near idle or idling like when i slowed to go around a corner or at a stop sign. once the RPM's rose the oil pressure rose to a safe range. what is causing this? the car runs great other than that.

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1986 Fiero GT
1992 Chevrolet Beretta GTZ
2000 Chevrolet Blazer ZR2
2004 Saturn Ion '2'

" I guess I've learned that there's more to life than racing, but not much more."
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2.5
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Report this Post05-21-2008 01:26 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Direct Link to This Post
For some cars that is normal, I'm not sure about Fieros, mine doesn't have a guage.
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aconesa
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Report this Post05-21-2008 01:38 PM Click Here to See the Profile for aconesaClick Here to Email aconesaSend a Private Message to aconesaDirect Link to This Post
Paul,

I can say that owning two SE's with V-6s, the pressure usually starts high when cold and when the engine warms up it will sit at about 20 during idle and up at 40 during normal cruising.

Abe
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Philphine
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Report this Post05-21-2008 01:48 PM Click Here to See the Profile for PhilphineClick Here to Email PhilphineSend a Private Message to PhilphineDirect Link to This Post
mine has done that since i changed my sending unit (the old one was keeping my fuel pump on, the sender part was ok). there was no other change at the time and i read sometimes a new sender will do this. so i look at it, but it's been that way for a while now. i can't say i don't worry at all about it, but i've kind of accepted it.

was a new sender part of your repairs? i think i also read that if it is just the sender, getting one for an '88 will work better, but i haven't tried it.
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jetman
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Report this Post05-21-2008 01:49 PM Click Here to See the Profile for jetmanClick Here to visit jetman's HomePageClick Here to Email jetmanSend a Private Message to jetmanDirect Link to This Post
Fiero gauges are famous for being inaccurate, get a real oil pressure gauge on there to find out for sure.

Yes, the oil pressure will drop when warm versus cold, as stated above, that's normal. Wear on engine bearings will cause lower oil pressure too as well as the type of viscosity you're using, length of time between oil changes.

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gunslinger
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Report this Post05-21-2008 02:29 PM Click Here to See the Profile for gunslingerSend a Private Message to gunslingerDirect Link to This Post
The main cause of that is the crankshaft bearings is worn and that is what is causing the pressure to drop or fluctuate while idling,eventually you will need a rebuild just use thicker oil with good bearings the pressure should remain constant.
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Report this Post05-21-2008 03:25 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Direct Link to This Post
Not in any vehicle I have ever been in. The oil perssure goes up with accelleration. And it will be high when the oil is cold, meaning not at 180 degrees.
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Francis T
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Report this Post05-21-2008 03:49 PM Click Here to See the Profile for Francis TClick Here to visit Francis T's HomePageClick Here to Email Francis TSend a Private Message to Francis TDirect Link to This Post
Could be a badly worn out engine, but since it's a lot easier to change oil pres sending units than to plasti gauge bearings, I would go that route first. I had the same issue with my 87GT, even made the idiot lite blink now and then. Changed the sending unit and the oil pres went right up no more idiot lite.
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fastblack
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Report this Post05-21-2008 04:48 PM Click Here to See the Profile for fastblackSend a Private Message to fastblackDirect Link to This Post
wow, thanks for all the suggestions guys. think i will try a new sending unit and go from there. i kinda want to replace that gauge and the volt gauge with some aftermarket ones, just still trying to figure out how to fit them in the original spot...thanks again

brian

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1986 Fiero GT
1992 Chevrolet Beretta GTZ
2000 Chevrolet Blazer ZR2
2004 Saturn Ion '2'

" I guess I've learned that there's more to life than racing, but not much more."
-Paul Menard

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