renegade123

So I go to start my 03 Z up the other day, boom out of no where
" Low oil pressure and check engine light " , so I am thinking it is the dreaded oil pressure sensor unit gone bad or possibly the oil filter even ?

Anyway, do an oil and filter change using the usual mobil 1 5w30 and start it up and hear some clatter up top, turn it off. Car is now stuck on the side of my driveway ( in gravel to make it worse )...Question is , should I even bother pulling the lower pan , or should I go straight to the oil pump - i'm guessing either the check valve in the oil pump is stuck closed, or the pump some how took a total crap ...car does not really burn oil, and only has about 65k on it.

Can I blow open the check valve by dumping a few extra quarts in it ? I know on the caddy northstar motors this can be done, but not sure on the LS6 .

1. Any benefit to pulling the lower pan first , is the pick up tube located in that, possible clogged screen ??

OR

2. Start ripping the front of the motor apart to get the timing cover off to remove the oil pump ?

renegade123

Thanks for any help guys..

555ss

Before I would rip it apart I would put a sensor in it to be sure that there is no oil pressure ( or use a mech gauge) then pull the lower pan the screens are very easy to clog....

renegade123

Definitely not a sensor only related issue, I am hearing noise up top that I was not hearing before the warning light, but I do have a sensor that I purchased to install later... Will check the lower pan first and see what the screen looks like, and if the pick up tube is some how loose or even disconnected ??

BTW, I had an idea if any one knows if this would work...can I blow compressed air up the pick up tube, and if I could get a decent enough volume of air up there, could that possibly dislodge a stock oil relief valve, or does this not even matter due to the way the pick up tube interacts with the pump ?? That is a crazy thought I had, OR maybe even forcing a large volume of oil up the pick up tube manually ???

At this point I am just looking to be able to start the car and move it safely onto my driveway from the gravel area of my yard before my home owners assn. starts pinching a fit, plus it is just not safe or comfortable to jack it up and work on it on the gravel...

Any ideas, thanks in advance

jbp8653

Mine did the same thing couple months ago. See my thread titled OUCH!!!!!. It was a wiped out cam lobe. Probably could of got away with a cam/lifters replacement but went ahead and did a total rebuild. Was fine then started making a slight spinning type noise then zero oil pressure. Try taking your oil filter off and cutting it in half. See if there is a lot of metal shavings. Mine had a bunch.

ezrider4u2

This sucks dude...I had something similar happen on a previous LS1 C5 and lost all oil pressure while driving. It was nothing that was easy to fix. I felt the engine "let go" and lose preasure. It was cam lobe issue as well. It caused other issues with the bearings and also lifters. I had all kinds of clanking going on. I ended up with a rebuild on my hands so I chose to upgrade that engine. I would start by checking to lifters since the noise is coming from upto. It is fairly easy to remove the covers and do a visual check for metal or other debris. If nothing there then go on to the lower end and check the filter and possibly pan..again looking for metal.

Atok

I would think you would have a little oil pressure even if the pressure bypass valve is stuck. Especially when cold. Sounds like it dropped the pickup off the pump?

renegade123

guess i'm pulling the lower pan to check the screen first , thanks...isn't there also a valve in the oil filter boss, would that have anything to possibly cause a problem ?

Coc5

Lifters.
Probably broke.
I know from experience. I went through the exact thing.

To make it easy.
Pull the intake and you can barely see the lifters.
Bad news isn't over.
When mine ate up the 4 lifters I had just a small ticking, then ZERO oil pressure.

Pulled the heads thinking it would just be a simple cam/ lifter replacement and get it back together.
I was WRONG!
When the lifters get eaten up on a LSX engine, the metal shavings drop onto the sides of the piston skirt!
Needless to say, I had BADLY steel inbedded pistons and ruined beyond use cylinder walls.
My solution was to build and installed an all forged LS6 and been REALLY happy ever since..

formerfoxbody

Pressure relief valve gets stuck open to cause a loss in pressure. You could gently tap on the block on the drivers side to attempt to free it. If you get lucky enough to free it then go buy a pump and replace it.

GMs temp fix is to dead rev the engine to build pressure to over come the stuck valve and free it.

LT1driver

and if not stuck and you rev engine you will only increase your misery.

bikeriderga

Since you are hearing engine clatter, I would not even attempt to crank it up until I did the following.

Take off the oil filter first, cut it in half and see if there is metal there. If not, then drop the pan.

If there is metal in either, you are going to have to tear into it and access the damage. If no metal in the oil, take the valve covers off and see if there is a broken spring, a valve that has dropped, or a frozen valve. Check the push rods and see if any look slightly bent, and check the rocker arms and see if any looks beat up or has excessive wear from where the push rods joins the rockers and on the valve tip points.

Check to see if a push rod can be moved rather easily. That MAY tell you if it is a potential lifter problem, especially if you bump the engine (don't start it up) and check each item in the above paragraph. If you discover any problems, that may tell you whether you need to tear into her before having to remove the heads.

Best of luck.

Atok

Any update? Curious as to what it was?

scott1974

So how did this turn out?