1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Low oil pressure 12a

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Old 09-22-19 | 01:31 PM
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rx7junkie170's Avatar
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Low oil pressure 12a

I bought a recently rebuilt 12a streetport for 1200. The issue I'm worried about is low oil pressure at the stock gauge.
This is the highest I ever seen it this was after I switched from 5w30 royal purple to 20w50 castrol gtx.
When the car warms up it drops down to 0 sometimes even lower then 0 but when I give gas at 3k rpm I'm at 30psi max even at red line alot of people say these gauges are old. Would this oil pressure damage my engine ?
Old 09-22-19 | 03:00 PM
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You won't "know" for sure what the real oil pressure is til you take a mechanical oil pressure reading. Remove oe sender unit and screw gauge in and start and run from cold til hot. See what oil pressure is at fast idle cold and idle speed when at operating temperature. Rev engine to 3k rpm and see what oil pressure is and post results here.

Looking at dash voltmeter,that's pretty low if car is running and might explain the low oil pressure readings. While car is running check voltage at battery with multimeter.

What do you have for an oil cooler? I could be confusing you with another member that was posting about aftermarket oil coolers,was that you?
Old 09-23-19 | 12:29 AM
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I did have A aftermarket oil cooler I removed it and I'm running the stock beehive
Old 09-23-19 | 04:16 AM
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You can rent oil pressure test kits from chain auto parts stores for a deposit that’s refunded when returned.

FWIW,I use Castrol GTX 20W50 conventional oil in my car and have for over 30 years.
Warm idle oil pressure registers center or just to left of middle line on dash gauge and cruise speed @ 65mph
is 7/8ths gauge travel or slightly less.
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Old 09-23-19 | 05:46 AM
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You will definitely want to install a mechanical oil pressure gauge, even if it's just temporary. Get an exact reading, as the original gauge or sender can be starting to show their age. If the pressure is the same with the mechanical gauge, we can dig in a it further and go from there.

I second the use of Castrol GTX 20W50. I've been using it exclusively for 20 years. I find that I have excellent oil pressure when using it. I dont run a weight lower unless I am forced to drive the car up until the snow flies. Then I'll go down to a 10W40, but nothing lighter.
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Old 09-23-19 | 07:49 AM
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I've found the gauges in the 84-85 to be inaccurate on more then a few cars, in particular the oil pressure gauge. They seem to lose there calibration over time and when off the needle parks too far past the low point of the gauge. I found an adjustment on the gauges where you can change the needle position (using a small phillips head) in relationship to the markings on the gauge. you have to take the front off to gain access. Just FYI, make sure the pressure is OK with a test gauge first...
Old 09-23-19 | 08:22 AM
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That condition is present on all 1st gens and every other car. Where the needle goes where car turned off is not an issue.
When the key is turned on,the gaugesoil,temp,volts,gas come up to their calibrated minimums and register This and actual readings are the only relevant parameters.
Old 09-23-19 | 12:43 PM
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One of the easiest way solve the problem is taking of the oilpressure sender and clean the small hole inside with brake cleaner.For getting of the 30 years old and hardened engine oil.
Old 09-24-19 | 10:06 AM
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Not to hijack the thread, but what's the best way to remove the pressure sender? I have an '84 with a beehive cooler and there isn't much room to get a wrench on it with all of the coolant and oil lines. Being that it appears to be a brass fitting, I was a little hesitant to crank on it with pliers to break it free. Would it be easier to access from under the car?
Old 09-24-19 | 01:48 PM
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It's easier to use a 14mm wrench on it. Pliers are gonna do more harm than good.

Access from above sort of in front maybe.
Old 09-24-19 | 02:24 PM
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I think part of my problem was I trying to use a 13mm wrench. Haha!
Old 10-10-19 | 07:19 AM
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Originally Posted by GSLSEforme
That condition is present on all 1st gens and every other car. Where the needle goes where car turned off is not an issue.
When the key is turned on,the gaugesoil,temp,volts,gas come up to their calibrated minimums and register This and actual readings are the only relevant parameters.
Please explain this to me and why are the gauges adjustable? The oil pressure gauge will sweep just fine, just doesn't read correctly in correlation to the print on the face of the gauge. My OP/water temp gauges only move after the car is started and begins to warm up..... No calibrated minimum with just the key on.
Old 10-10-19 | 09:38 AM
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Another reason to love the SA, no extra gauges! LOL
Old 10-11-19 | 12:09 PM
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Originally Posted by t_g_farrell
Another reason to love the SA, no extra gauges! LOL
I did not need to have any passion searching any reason to love my FB!😘

Last edited by Rx7fb spirit r; 10-11-19 at 12:11 PM.
Old 10-11-19 | 07:45 PM
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Originally Posted by Rx7fb spirit r
I did not need to have any passion searching any reason to love my FB!😘
How could you not love an FB?? Its just like an SA, but better..
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