Just recently my oil pressure went from good to almost not there. in a matter of a day or two. At 1.5K its barely at the first line above the red zone. At idle its IN the red (after warms up) and the "check guages" light goes on. after setting for a few hours then starting it up the pressure isnt normal either (not at around half like usual) its below first line still. Doesnt increase much at all with RPM increases.

Might be some engine noise, not sure i parked the car untill issue is resolved.

For years i have ran Amsoil 0-30 signature racing oil and the amsoil AE oil filter with no issues. Ran a seafoam threw engine last oil change for 200mi highway trip and changed right away.

Will replace filter to check that. Replaced the oil pressure switch already too.

Best way to check the screen/pickup? Is this my pump?

 

Could be the thin oil just took its toll? Ive seen the oil sending units go bad and act like this but you said you already replaced it. Could be you got a defective one. Probly try getting ahold of a manual gauge and see what it says.

 

I have heard of several times that someone ran seafoam through the engine on a higher mileage vehicle only to have bad results. They broke a lot of the engine sludge loose that was there for years and plugged the oil pickup and other things. If you ever saw the inside of a motor that was even slightly abused you would see what would happen if that ever came loose and got in the oil supply. Not sure that exact thing to do, but I would start by changing the oil and filter and see if that helps. Maybe need to drop the pan and check in there. Just an idea.

 

the screen/pump is cheap, just doing it is going to suck! is there a way to check screen/replace without completly removing pan?

 

Before tearing the oil pan off try testing using a mechanical gauge. You can tap into the oil passages through a port just above the oil filter. This will confirm that you actually have low pressure.

Low oil pressure is usually a cam bearing issue. Changing the pump won't help. I would think you can test this out by increasing the oil's viscosity...try running a 20 weight and look at the pressure....

 

The place to hook up a mechanical oil pressure tester is by the oil filter?? Where? My pressure switch is by the fuel rail.
Nobody thinks the pump could be out? I work at az and can get a pump for dirt, and a rebuild kit for 455. Rebuilding this would take me a month or more! :-(

 

Courtesy of Shoebox:

http://shbox.com/1/aux_oil_port.jpg

Not sure why anyone mentioned "thin oil". While 0W-30 will flow better on cold start at extemely low temperatures (and not like likely to be encountered), once the engine is at operating temperature, it's a 30 weight oil, which is EXACTLY what GM recommends for the engine. It is not going to "take its toll".

I don't think anyone is ruling out any particular problem. We are just suggesting that you check the pressure with a mechanical gauge to rule out the possibility its a problem with the oil pressure sensor or the dash gauge.

 

Fixed it!!!!! Just changed the filter, looked like a turd came out the filter shaft. Put a Mobil 1 filter in and perfect!!! Now just engine flush and a few oil changes then back to my amsoil. Thank you everyone!

 

What brand was the oil filter?

 

amsoil absolute efficiency. Changed the Mobil one filter to a k-n filter after I did the flush and it was ok. It's way way better at upper rpm but goes to red now after hot in idle but great pressure driving. Used Mobil 1 5w30. maybe my pickup is loaded. any ideas before I assume its that and pull pan.

Is the k.n filter not too good for this car? It was a lot longer then the Mobil 1

 

My guess is there is still gunk in there somewhere. It might be smart to check it, but it is a pain also.

 

This might sound a bit out there but just for peace of mind next time you drain the oil for a change bang on the bottom of the pan not too hard just enough to see if you can hear any rattling goin on in there. It is possible that your pickup could have fallen off and is sittin on the bottom of the pan its happened to me twice and to a friend once so it's something that cant be ruled out it only takes a few seconds to check I doubt that's your problem but a few seconds can save you from having to rebuild your motor. I drove around off and on for 3 months with the pickup floating around in the pan I had the same symptoms at idle oil pressure would drop to 0 and check gauge light would flash only if the car was warm. I switched to a 20/50 oil and it seemed to go away until I took it to the track big mistake smh. Like I said it wont hurt to check.

 

so i stuck a mechanical guage up to it. when my needle is IN the red, my mec guage says 20psi still. my cluster might be bad? or is the area where the oil sw is connected to a little clogged?

If so ill turn it on w/ out a guage in there for 3 sec to shoot it all out, ill make a mess, but oh well.

is the AutoZone pressure switch not good for our cars? (i work there) should i get oil pressure sensor from GM?

 

Yes! I had the same problem a couple weeks ago, i got a bad o/p sending unit from O'reillys and had the same symptoms your having, i went straight to my local gm dealer and bought an acdelco sending unit, it's expensive but definitely worth the money and i'm glad i dont have to fork over the cash to get the dash cluster worked on! My mechanics mechanical gauge said i was at 20lbs of o/p at hot idle my new acdelco sending unit is just a hair below that on the gauge, the acdelco unit is pretty accurate with the stock gauge.

 

The gauge cluster is what it is....inaccurate. That's why we suggested the mechanical gauge. Before buying anything, remove the wire from the sensor and check the gauge reading, ignition ON. Should be maxed out on the scale. Then ground the wire and repeat. Should read zero. If it does the gauge is working correctly.

I recommend only using AC Delco or Delphi sensors...while they could be made anywhere they always seem to be made to OEM criteria.

Chances are that your problem will disappear when you use the AC Delco sensor....