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07-19-2007, 01:42 PM | #1 |
Registered User
Join Date: Feb 2007
Location: Central Florida
Posts: 166
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Oil pressure fluctuation
A quick question for anyone out there. I was wondering if it is normal to have your oil pressure fluctuate on your truck. I am talking when cold it is around 50psi or so and after warming up it may drop to 30psi at an idle, and then during driving go back up to 50psi or so. I have always thought this to be normal, what do you guys all say about it.
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07-19-2007, 02:03 PM | #2 |
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Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
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Re: Oil pressure fluctuation
My 69 Chevy used to do the same thing. (not running right now).
Pressure was always higher until it warmed up then it would go down when idling at a stop and I could rev it up and see it go up again. Ran it that way for many years with no problems- then I did an overhaul. Wear was the problem. Redid the crank and put new bearings, rod bearings, rings, oil pump, redid the heads, etc. Still had some fluctuation but it helped quite a bit. Depending on how many miles on your engine could be just a worn oil pump or crankshaft bearings. |
07-19-2007, 02:45 PM | #3 |
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Join Date: Apr 2005
Location: Joppa, Maryland
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Re: Oil pressure fluctuation
That is normal........
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1997 GMC Sierra Ext 1965 Mustang |
07-19-2007, 03:11 PM | #4 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
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Re: Oil pressure fluctuation
30 at idle warmed up is fine
50 when cold is fine too this is all normal |
07-19-2007, 04:52 PM | #5 |
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Join Date: Feb 2007
Location: Central Florida
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Re: Oil pressure fluctuation
Thanks for the quick replies all, I figured it was all normal since mine trucks always done it. They are all the higher 100k+ mile stuff so that sounds good.
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07-20-2007, 06:40 AM | #6 |
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Join Date: Dec 1999
Location: Old Mission, MI, USA
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Re: Oil pressure fluctuation
It does not need to be that high at hot idle. 10 psi is fine. 5 psi will work just fine also, but that is the time to start thinking about what might come next.
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Tim |
07-20-2007, 08:44 AM | #7 | |
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Re: Oil pressure fluctuation
Quote:
True.. Mine was dropping pretty low on warm idle and decided to overhaul. It was running okay but was also smoking on startups. So, if it's still running good, mileage and oil consumption are normal and it's not clattering or clunking, keep on driving... |
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07-20-2007, 08:50 AM | #8 | |
Hittin E-Z Street on Mud Tires
Join Date: Nov 2004
Location: Greenville, SC
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Re: Oil pressure fluctuation
Quote:
I think your truck is fine
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07-20-2007, 03:36 PM | #9 |
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Join Date: Jun 2001
Location: Benton, AR "The Heart of Arkansas"
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Re: Oil pressure fluctuation
Generally, 10psi per 1000rpms is a good rule of thumb for a warmed-up engine.
My truck pegs the guage when it is cold....80+psi. When it is hot, it's less....waaaay less. I'm into the beginnings of the thought process of getting a Goodwrench 350 longblock to relieve the 220K (or 320K) original engine in my truck. It's been built once, I was told, but not by the previous owner, who had it for nine years and I've had it for eight.
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Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. |
07-20-2007, 04:05 PM | #10 |
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Join Date: Feb 2005
Location: Carl Junction, Missouri
Posts: 2,061
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Re: Oil pressure fluctuation
i wish i would of known this with my old engine, it never got more than 12 psi. i was always burning bearings... i didn't know the oil pump was bad until my new crate 350 ran alot higher pressure.
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