Oil Pressure opinions wanted

**transamdave** · 03-15-2012, 03:11 PM

Ok here goes My T/A ls1 68000 2001 oil pressure at start up about 43 lbs idle after driving 30 minutes goes to about 5-7lbs in gear at idle
That said tried couple different oils finally changed to synthetic 10-30 valvoline and mobile one filter high capacity no difference with any. Car runs great idles great temp is steady about 200degrees and the motor makes no noise at all not a tick clunk nothing. I would say sending unit but it flucuates so much. Another question can i take the thing off above oil filter to hook up oil pressure gauge there is that the place people talk about with the 2 small bolts holding it on? Im really interested on any knowledge if anyone has hooked up a gauge here!!

***SMWS6TA*** · 03-20-2012, 01:05 PM

Sorry no one has replied to you, this kinda got buried. You would have been seen if it was placed in the "General Help" section.

Now to hopefully answer your questions....

That pressure reading is critically low. In fact I would not drive it anywhere until you find the problem. You should be at minimum running around 40-45 lbs at idle and in gear with rpms in the 2000-3000 range around 55-65 lb range.

Now best case - it's the OPSU. Worse case your oil pump is fixing to shit on you.

Check the OPSU first - on the drivers side just behind the intake the OPSU sits there. Use a mirror and a flash light or reach as best as you can try to feel around for some oil. If the mirror and light can shine on the OPSU look for obvious cracks.

Post back what you find.

Some have installed aftermarket OPSU's but seeing that I have not I won't pretend to explain how it's done. I've heard of swapping out the stock OPSU and also tapping into the bracket next to the filter and setting up that way.

**transamtom** · 03-20-2012, 04:02 PM

Changing the OPSU is almost impossible with the intake on.

You are going to need a special socket for it,the socket is about $8 at most parts stores.

Use a genuine GM OPSU the shitty aftermarket ones fail and you will be doing it again soon.

**transamdave** · 03-20-2012, 05:25 PM

I think im going to get it plugged into a good scanner. I can do that with this car correct? I have also learned (I am learning every day about motors) that oil pumps dont create oil pressure, bearing spacing does. Is this a correct statement, kind of? I have also seen pictures of how to attach an aftermarket pump on the other website.

***SMWS6TA*** · 03-20-2012, 05:30 PM

bearing spacing and a lot of other things to effect oil pressure, however if the oil is not moving no pressure can be achieve.

Checking the OPSU like I posted is the cheapest and easiest thing to look at FIRST.

I'm not sure what you are looking for with the scanner, as far as I know scanners can't read our oil pressure due to them being mechanical gauges. Otherwise I don't think they are sending a signal to the PCM. I may be wrong, I won't profess to say I know all with our cars.

100% agree with Toms post about using a GM OPSU.

**transamdave** · 03-21-2012, 04:11 PM

I hooked up and aftermaket gauge and it reads the same thing. Dont know what to do at this point its a guessing game for me.

**madmike90** · 03-22-2012, 03:32 AM

it can be either the bearing clearances being too large from wear and causing an oil pressure drop when the engine warms, or a failing oil pump, or even a stuck oil filter bypass. (that one threw me for a loop on a sbc before)

***SMWS6TA*** · 03-22-2012, 09:18 AM

well now that you hook up a pressure gauge and it reads the same I now believe that the oil pump is either gone or is fixing to go.

Recommend getting a LS6 oil pump at least, port & polish will give a little more flowage.

**transamdave** · 03-22-2012, 04:40 PM

Well it all gets a little more strange today its running hot at idle in gear at 13lbs, in park at idle around 18lbs, that being said it was also running 10lbs higher than normal, I am going to get it looked at in a couple weeks but im wondering if maybe the motor is sludged up from previos owners. I have only put about 1000 miles on the car with 2 oil changes, maybe........ well I dont know just seems a little strange hook up a gauge and next day things get better dont make much sense im so frustrated. Btw does the ls6 pump push better or just better design?

***SMWS6TA*** · 03-23-2012, 12:23 PM

a little of both. I'm not sure what the internal differences are specifically but it flows more the the stock LS1 does.

when both are about the same price it is always better to get the LS6. I know of no one that recommends getting a LS1 oil pump.

**bhunter0830** · 04-17-2012, 02:57 PM

So what was thee verdict? I'm curious on the oil pump. Mine runs about 50 at start then drops to around 40 after warming up. I have been using Shell Rotella D and the pressure stays up. Also cleans better than 10w30 or 5w30.

**pajeff02** · 04-17-2012, 06:16 PM

The general rule of thumb is that you want at least 10 psi for every 1,000 rpm. Curious as to how the aftermarket gauge was plumbed into the system -- did you tap into the existing sender's circuit or was a new sender installed in place of the stock OPSU?

**transamdave** · 04-22-2012, 05:19 PM

Well its still the same steady the same every day I watch it like a hawk. I took that little piece off above the oil filter and tap it out with pipe tap and hooked the gage in there. There is a couple pictures of that on the other ls1 site. Took me about half hour and was very easy. Two bolts took it off, drill and pipe tap it (im a machinist buy trade so that was easy for me) hooked brass tube kit to gauge fish it back in 2 bolts and balla bing done.

I was to scared to take out the stock 1 out

**pajeff02** · 04-22-2012, 05:28 PM

I was looking something else up in my service manual and happened to see the oil pressure specs for our engines... the numbers were actually lower than I thought they would be.

**transamdave** · 04-22-2012, 05:53 PM

What did it say in your manual?

**pajeff02** · 04-22-2012, 05:57 PM

How did I know you were going to ask that? Give me a minute to go get it from the garage.

**pajeff02** · 04-22-2012, 06:00 PM

Here's what it states:

Oil Pressure (Minimum - Hot)

At 1,000 RPM - 6 psig
At 2,000 RPM - 18 psig
At 4,000 RPM - 24 psig

I left out the metric equivalents.

**transamdave** · 04-22-2012, 06:03 PM

Oh my so i guess im plenty good. It even says in the owners manual that pressure can get as low as 6lbs and still be normal.
Thanks for the info bro

**tatertot91** · 04-22-2012, 06:03 PM

Originally Posted by pajeff02

I was looking something else up in my service manual and happened to see the oil pressure specs for our engines... the numbers were actually lower than I thought they would be.

Just made me check my books, 6psi around idle doesn't sound acceptable to me