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Author Topic: ENG OIL PRESSURE  (Read 3433 times)

Offline CashpitC10

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ENG OIL PRESSURE
« on: November 20, 2019, 01:48:38 pm »
Have 83c10 with a 305 just changed oil less than a month ago. When i stop at a red light or stop sign the oil pressure drops below 20lbs. What could be the cause of this? Any help would be great.    Thanks Jody
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Online bd

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Re: ENG OIL PRESSURE
« Reply #1 on: November 20, 2019, 02:08:06 pm »
Have you checked the oil level?  How many miles on the engine?  What's the oil pressure at 1,500+ RPM?  Was there a sudden decrease in oil pressure at idle or has it been this way for some time?  Have you verified the oil pressure using a manual test gauge or are you relying on the factory dash gauge?
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Shifty

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Re: ENG OIL PRESSURE
« Reply #2 on: November 20, 2019, 04:06:19 pm »
The olde small-block Chevy formula was 10 pounds per 1,000 rpm, if that means anything to ya.
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87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline bedwards

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Re: ENG OIL PRESSURE
« Reply #3 on: November 20, 2019, 06:54:49 pm »
If your talking factory gauge, they are notoriously inaccurate.
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Offline Shifty

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Re: ENG OIL PRESSURE
« Reply #4 on: November 21, 2019, 08:33:48 am »
Quote from: bedwards on November 20, 2019, 06:54:49 pm
If your talking factory gauge, they are notoriously inaccurate.
Agreed.  According to mine, I should be pushing the truck instead of driving.  :o
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87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline JohnnyPopper

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Re: ENG OIL PRESSURE
« Reply #5 on: November 22, 2019, 01:29:07 pm »
Are you using a multi viscousity oil, like 10-30?

Might be too light for a truck with high mileage.

Could go with a single vis oil, or move up to 20-50.

You don't hear knocking or rattle when that happens do you?
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1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction
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