Oil Pressure?

[Racinfan83]

What do your cars run for oil pressure when hot? Out driving today and at 2k rpms or so (cruising) the dash guage reads about 40. At idle it drops to near 0 and needle fluctuates a bit. No knocking or anything from engine. Runs fine. Oil was just changed less the 200 miles ago. Mobil 1 10 -30. Thoughts?

[Dynomite]

A bit low especially at idle.......I run from 60 to 50...maybe 45 at slow idle. Exchange the Gage Oil Pressure Sensor (the one that sits vertical in front and on top of Oil Filter Housing) to see if any difference.

[Racinfan83]

Is that sensor something u can get anywhere or is it one of those hard to find deals?

Think I found em on Amazon D1808a...

Just went out and checked oil after car sat for couple hours. It looks fine. Started it back up, oil pressure at idle was about 35-40 by the gauge, 60 or so revved up. Idle pressure was about 20-25 after engine got to 220 degrees or so - needle fluctuated a bit. When the A/C compressor kicks on it drops the idle way down and I hear a rattle from rear of engine. Other then that it doesn't knock. This car has 18k miles on it... Gonna order the sensor but any other ideas are welcome....

[Dynomite]

When the A/C compressor kicks on it drops the idle way down and I hear a rattle from rear of engine. Other then that it doesn't knock.

That rattle is Dual Mass Flywheel....which is normal at low idle :D
I think that oil pressure sensor is a three pin sensor.

[A26B]

The rattle from the rear of the engine is probably the dual mass flywheel if the idle is lower than 700.

Engine rpm is supposed to go to high idle when the AC is on.

I've never been a fan of electronic senders for critical engine conditions, so I installed a pillar mount, direct reading oil pressure gauge. Short of that, I would recommend that you at least temporarily install a gauge in the 1/8"npt hole where the oil pressure sender goes, just to confirm a "real" reading. Then you can correlate that to the analog display on the dash & have a better idea what is real.

FYI, there is a separate, low oil pressure "switch" that will illuminate for low oil pressure. Given that you are not seeing that, and the analog needle is fluctuating, I agree with Dynomite that the sender is probable faulty & should be replaced.

[Racinfan83]

Thanks! I took a video of it - trying to get it uploaded so u guys car hear it...

[efnfast]

Hey, do you think Jerry's gaskets has those?

[Racinfan83]

Here is a video I just took of starting it and running with the A/C on:

http://www.youtube.com/watch?v=9WrCX0z7-KQ&feature=youtu.be

[Racinfan83]

Hey, do you think Jerry's gaskets has those?

Hopefully :):cheers:

[ghlkal]

At idle it drops to near 0 and needle fluctuates a bit.

Every once in a while my gauge drops to 0. The first time I noticed this, I freaked out. I threw it into neutral and was about to shut it down when the needle shot back up. Hmm ...

BTW, it's hard to tell what the analog gauge is reading as the gauges are "non-linear."


Exchange the Gage Oil Pressure Sensor (the one that sits vertical in front and on top of Oil Filter Housing) to see if any difference.


I've never been a fan of electronic senders for critical engine conditions

I assume my problem is this sensor, and I've learned to live with its occasional 0 reading :jawdrop:

Jerry made a good point about the "oil light." Since I don't see that, I assume I really have oil pressure even when the analog gauge shows 0 for a few seconds.

[Toyvet1]

Had the same issue. Replace sending unit and all is fine now.

[Racinfan83]

Well I started it up this morning and it went up to like 60psi at idle. Thinking that if there were an issue internally bad enough to create 0 on the gauge it wouldn't read 60. Gonna see if Jerry has a new sensor...

[Paul Workman]

Sounds like it could be the sender. And, then again, the dash instrument cluster board contacts have been known to get "frosty" (read: oxidized), requiring some cleaning and some contact cleaner spray.

I agree w/ others on the sender, and I'd begin with the sender. It is easy to replace, and more likely the culprit, from my experience with senders (in general), especially with a car that has sat for extended periods (as I'd guess yours has seen some extended periods with little running).

p.

[Dynomite]

Sounds like it could be the sender. And, then again, the dash instrument cluster board contacts have been known to get "frosty" (read: oxidized), requiring some cleaning and some contact cleaner spray.

I agree w/ others on the sender, and I'd begin with the sender. It is easy to replace, and more likely the culprit, from my experience with senders (in general), especially with a car that has sat for extended periods (as I'd guess yours has seen some extended periods with little running).

p.

Might add.....that electrical connector plug on gauge oil pressure sending unit is finicky sometimes and checking/wiggling the electrical plug on top of the oil pressure sender may solve incorrect dash oil pressure readings.

[A26B]

..... Gonna see if Jerry has a new sensor...

I'm out right now, presently sourcing in AC-Delco for stock.

In the meantime, try this for a source local to you.
http://www.oreillyauto.com/site/c/search.oap?keyword=d1808a&year=1991&make=Chevrolet&model=Corvette&vi=1041297

[Racinfan83]

Cool - thanks guys! I will clean the contacts and see what happens. Then I will see about getting one. Nice to know that it isn't an internal engine problem....

[Racinfan83]

UPDATE: I ordered the sending unit from Jerry's, replaced yesterday. Seems to read MUCH better now. It is a 5 minute fix just to let those who may have oil gauge problems know.