renatogfofo

Hi All, I am new here. My 1994 LT1 with 76,xxx miles is having low oil pressure issues. I replaced the sending unit and it got worse. when the engine is hot and I stop at idle I am getting 5~6 PSI. The pressure does go up when I accelerate. Any ideas? Thanks all.

Nowhere Man

Are you low on oil? What weight oil are you using. That low your engine should be making a lot of barring and lifter noise.

billschroeder5842

Yikes! At that low of a rate, I'd throw a "real" oil gauge on the engine and not rely on the dash board.

Hopefully it is just your gauge getting wonky.

Paul Workman

Use a mechanical gauge and first verify you have a problem and not a gauge issue.

renatogfofo

no bearing noses. No knocking at all.. 5w/30 oil.

Nowhere Man

Then if your oil smells and looks good and on the full mark then as others said check with a known gauge

renatogfofo

Oil is good, clear, clean, and no knocking. I am taking it to a Vette shop near my place. I hope its nothing major. engine has only 76K miles.

LTxDave

First recommendation is to use a mechanical gauge as others have noted.

If the engine has been questionably maintained, it could be the oil pump bypass valve stuck open. If the mechanical gauge confirms low pressure, I would add a little ATF to the oil and see if it loosens up the valve and pressure goes back to normal.

net_coma

Did you/when you resolve the issue please share.
My 69k 94 idles at about 20psi when at normal operating temperature, kinda scary.
On one of the Camaro boards that I used to visit there are lots of lt1 oil pressure and spun bearing issues. I have never read or heard a reasonable explanation for these issues. Rotating assembly is the standard small block chevy, yes? Never had any of these problems with my small blocks and the lt1 does. I was at a local salvage yard looking for treasure soon after the lt1 went into service and was talking to the guy rebuilding one. His comment was that people put in oil other than 5w30 and cause engine problems....for what it is worth, I have no clue.
The only thing I don't like about my vette is the lt1 unknowns where it is unknown because it is or because I am still learning about the engine.

If the issue was bad sending units provided by GM then we would all know, this far I have not found anyone that can explain it to me. Low oil pressure is our nightmare. I don't care what GM says about the pressure necessary to float a bearing, it makes me want to wine.

FAUEE

5 psi, or even 20 pai, is WAY too low even when warmed up. My car has 140k on it or so and runs 40 psi when warmed up.

I'd confirm that the gauges aren't just wrong, and of they are right I'd be very worried.

LTxDave

GM seems to think otherwise... Factory service manual.

FAUEE

Interesting, I could be wrong but I thought the middle point of the oil pressure gauge was 40 psi, that's wh er re mine stays...

scrappy76

All the gm motors I have had ranging from v6's to big block v8, Have had anywhere from 8 -25 at idle and 40-60 cruising down the highway. This is at normal operating temps.
I had a v6 once that idled at about 8 psi and 30 cruising, no noises and ran great.
The rule of thumb I always heard was 10 psi for every 1,000 rpms is good.

Put a mechanical gauge on it and let us know.

leadfoot33

what scrappy said, we use that rule of thumb in our racecars as well.
my L98 at its peak heat (just before the fan comes on) is around 26-30psi at idle in gear, as soon as i hit the throttle its back up around 50.

check with a mechanical guage and go from there.