Low Oil Pressure???

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OkieFishMan

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OkieFishMan
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1984
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GMC C2500
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454/SM465
Alright, so I have been working on my '84 C2500 and the 454 seems to run great. I pulled my gauge cluster out and cleaned the contacts and printed circuit and the gauges now all work. But I have noticed the when I start the engine cold, the oil pressure will show 30lbs or so at idle. Once its fully hot, like after a 100 mile drive, the oil pressure will be zero on the gauge at idle. The engine makes no sounds to indicate that it has no oil pressure, no lifter noise or anything. So are the factory gauges innacurate?? What gives?

Thanks!
 

yevgenievich

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I had a gauge that was partially bad. Showed 30 cold and 10 hot. When checked, actual pressures were 70 cold and 30 hot at idle.
Could be acurate, or could be a bad reading
 
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Cuba

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No way to really tell unless you use a mechanical gauge to test. Then you can be sure one way or the other & make note if really off.

But I doubt it's at zero when warm...lol could be a loose connection at the pressure sender or it's starting to fail. Not very expensive if it turns out to be the sender.
 

foamypirate

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Big blocks are notorious for making poopy oil pressure at idle, too.
 

smoothandlow84

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It sounds like just a bad gauge.
 

74 Shortbed

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If there was zero oil pressure there would be lifter clatter, according to GM techs it takes only 7lbs to float a big block assembly..
 

highdesertrange

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first off find the specs and test the sending unit. highdesertranger
 

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