Low Oil Pressure.

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Nov 14, 2003 | 03:14 PM

jrzvette

Thread Starter

Safety Car

Joined: Sep 2002

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From: The reason time exists is so everything doesn't happen at once

Low Oil Pressure.

I think my oil pressure gauge or sending unit may be faulty. Sometimes it will show approx. 35 lbs at cusing speed, other time around 5.

Where would be the best place to hook up an external pressure gauge?

thanks

Nov 14, 2003 | 03:28 PM

Surfer69

Drifting

Joined: Apr 2002

Posts: 1,720

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From: Manhattan Beach Ca

Re: Low Oil Pressure. (6t9l4t6)

I had many issues with low pressure, especially at hot idle I was around 8 psi.
What I found was temp and idle rpm setting can help out the situation or high vol pump. My gauge was off by at least 7-8 when I compared to two other more expensive gauges.

You can test at the block or by the filter.

Nov 14, 2003 | 04:41 PM

Chuck Gongloff

Race Director

Joined: Apr 1999

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From: Beverly Hills/Pine Ridge Florida

Re: Low Oil Pressure. (6t9l4t6)

If you have a 69, I believe that you have a mechanical gauge...no sending unit. SO.....check for leaks in the tubing, etc. Check for leaks behind the gauge bezel...dripping oil on the top of the radio. The mechanical gauges are pretty accurate. Is this a "new" problem? Have you done anything to the motor? Changed oil with a lighter weight? Running very hot? Gas in the oil causing it to thin out? Chuck

Nov 15, 2003 | 09:19 PM

Vette Named Danielle

Intermediate

Joined: Dec 2002

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From: Magnolia Ohio

Re: Low Oil Pressure. (Chuck Gongloff)

My '81 runs just a touch past 40# normally. What's normal for an '81?
I'm used to most cars pushing close to 80#. :auto:

Nov 15, 2003 | 09:26 PM

77L82_4speed

Advanced

Joined: Oct 2003

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From: Amelia OH

Re: Low Oil Pressure. (6t9l4t6)

My 77 runs about the same as your 81. Probably right above 40 at highway speeds

Nov 17, 2003 | 11:22 AM

jrzvette

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Safety Car

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From: The reason time exists is so everything doesn't happen at once

Re: Low Oil Pressure. (Chuck Gongloff)

Quote:

There are no leaks either inside the car or from the engine. The problem occurs occasionally for a while and then goes away. I'm using 10W30 oil and have done so since I've had the car (about 7 years). As for temp. the gauge usually shows just shy of 195*. If I sit in traffic for a while it might creep past that mark but drops back as soon as I get back to highway speed.

Nov 17, 2003 | 04:43 PM

pws69

Melting Slicks

Joined: Nov 2001

Posts: 2,668

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From: Eastern US XX

Re: Low Oil Pressure. (6t9l4t6)

Quote:

I had one that did that and eventually dropped to a steady zero! Turned out to be the gauge movement - a little corrosion or something caused the movement to bind. Took the gauge out, sprayed it with some WD40, let it soak, and sprayed again. I then made sure that a VERY slight pressure would deflect the gauge. It's been working fine for over a year now.

[Modified by pws69, 4:44 PM 11/17/2003]

Nov 18, 2003 | 04:56 AM

Turbo-Jet

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From: Vancouver BC, Canada

Re: Low Oil Pressure. (6t9l4t6)

Connect a 2" 0-100 psi, glycerin-filled gauge directly to the NPT fitting in the block replacing the current gauge line block fitting. Use suitable 1/4" hose, and minimize the length for the fastest response time. Drive around and record the pressure at various rpm’s and temperatures. With the large hose, you should be able to detect any sudden deviations indicating flow problems.

Possible things to look for if you verify low or irregular pressure:
-pick up screen securely attached and set to correct height
-pump gear clearance
-internal leaking from pump cover, relief valve or block interface

Once you’ve got the pan off, might as well replace the pump. No need at all for a high-volume pump.