1994-LT1-Eric

Hi all,

I've been having low oil pressure recently. It averages just above the red line at idle. The car sat in my garage undriven for almost 3 years, but I changed all the fluids and had some work done (had to replace fuel pump, repair some wiring etc)...

I had an oil change about 3000 miles ago (about to change it again) and they put 5W30 in. The car now has 111000 miles on it, and I was thinking for the hot area of Texas that I'm in, 5W30 is too light?

The only other things I could think of is maybe the screen in the oil pan is clogged, or maybe the oil pump isn't putting out as much as it should. The dipstick reads in operating range when cold.

This morning I started it and went to make coffee, came back and it had shut down, bogged out with no oil pressure, and the temp had gone up a bit, but not critical. I don't have any idle issues or tune problems that I know of, the car runs good with the exception of this oil pressure thing.

Curious

1994-LT1-Eric

No ideas on low oil pressure once up to operating temp?

Injuneer

What is the pressure at various engine RPM? GM accepts 6psi as adequate at idle on the LT1. A very general guideline is 10psi per 1000RPM.... e.g. 20psi at 2,000rpm, 30psi at 3,000rpm, etc.

How hot does your engine run under those various operating conditions?

Have you checked the oil for fuel dilution?

Have you verified the dash pressure gauge reading by using a quality mechanical pressure gauge?

1994-LT1-Eric

Hi,

I don't have any guages to get readings that way (yet), so I'm just going off of the instrument panel.

The oil pressure at cold start is between 40 and 50, then once the car gets to about 200 on the temp it'll start dropping and ultimately settles at about 12psi or so, but I can see it dipping every now and then, without exhaust note or RPM changes.

On the oil guage in the instrument panel the low side has two red lines for critical pressure, when the temp is 200 (mid way through the temp range) the oil pressure indication (needle) is halfway between the second red line, and the first white line.

When my temp starts to crawl past 210 the fan kicks on, cools it off and it starts dropping back below 210.

The problem seems to be intermittant...All the above is at idle. I did take note of pressure going up with throttle/rpm changes but I havne't logged them yet.

Looking under the car, I just realized (saw) I have at least one small exhaust leak prior to the gutted cat ...unrelated I'm sure.

Sorry for the unscientific responses, I'm just now getting geared/tooled up on this restoration of my old car.

Injuneer

If the exhaust leak is blowing hot exhaust on the oil pan, it could be contributing to the problem.

1994-LT1-Eric

That's exactly what it's doing. I'm looking into getting long tube headers but can't decide on hooker or pacesetter. As noted in my sig I have a borla catback.

I've been reading like crazy and watching videos trying to decide what I'll need in regards to tools etc for doing this job myself. I'm scared hahaha

I'll need to replace everything from the headers to the gutted cat I have, which I'll probably end up replacing.

But I digress. I ran the car today around town and haven't had it drop again like I've seen on rare occasion. With this problem being intermittant, I believe it's going to be one of those replace components until it disappears. Which is fine because I'm restoring anyway.

Thanks again Injuneer!