ls1121

So here's the deal, This morning I started my 08 Z51 and the DIC says "NO OIL PRESSURE". The gauge was on zero and maybe 30 seconds later the gauge went to 40, 40 has always been normal. As i'm driving now (all day) when I come to a stop the pressure drops to around 20 and as I increase speed it'll go up to 60 psi and then when I get to a cruising speed it goes to 40 psi. Every time I stop it's the same routine. My first thought was the sending unit but after some thought (very little) I'm thinking no. Is it possible i'm having an issue with the oil pump or some other thing?

Anyone else ever have something like this? I've had this car almost 6 years and when I would start it up it always just went to 40 psi and stayed there.

wayback

When my oil pressure sensor went bad it read 80 psi.

You can power up the gauges without starting the car and see if your showing any oil pressure. If you are it is a bad sensor.

Corvette_Ed

I'd say it's probably the sending unit. They're known to fail, and they act crazy when they do.

Lee Cromwell

Is it sounding the same, ie, no ticking etc.. my money is on the sending unit too and before I did anything else I'd replace that with a new unit and see from there.

sprayer

How do you do that? Have not figured a way to check the DIC panel without starting car.

EVRose

Hold the bottom half of the start button down for about 5 seconds or until it's in ignition on mode.

Dano523

Easy fix, but you not going to like it.

On the back of the engine on the top valley cover plate, is your oil pressure sensor.



So if you are right handed, from the drivers side of the engine bay, reach your hand under the windshield cowling to the back of the motor behind the intake manifold, pop the oil sensor connector off the sensor, wedge your other hand in with some spray contact cleaner and spray both the connector and senor pins, then snap the connector back onto the sensor: all while doing by feel alone.

Use the red can of spray contact cleaner, not the blue can,


Do not get savage and cut a hole in the cowling like the photo shows, but the photo is to give you an idea of were you are reaching blindly under the cowling to get to the sensor connector isntead.





If cleaning the connector and sensor does not solve the problem, then next step it to replace the sensor. Granted that removing the intake manifold makes replacing the sensor a lot easier, it not needed, and with some special tools like a short socket and extension swivel, you can remove and replace the sensor via feel alone.

If you have to see what your doing/suck working by feeling alone, then get a snake camera for some to point at the sensor and show you the screen so you can see what your doing instead.


As for oil pressure, once the car.oil warms up, at idle should be at 30 lbs, and as the rpm's rise, the oil pressure will as well. Oil pressure below 25lbs at idle is a problem, and if the pressure sits at 80lbs, the oil sensor went south instead.

Since your gauge is working after a few mins, would bank that the problem is just the sensor plug connector pins need to be cleaned.

Batman75

[QUOTE=Dano523;1597234702]




As for oil pressure, once the car.oil warms up, at idle should be at 30 lbs, and as the rpm's rise, the oil pressure will as well. Oil pressure below 25lbs at idle is a problem, and if the pressure sits at 80lbs, the oil sensor went south instead.

Have you informed GM their OM is incorrect? It says normal oil pressure is between 20 and 80 PSI. It also states pressure below 20 psi when idling for a long period is also normal. The low pressure warning on the DIC doesn't light up until 3 psi.

sprayer

Good stuff will give it a go.

ls1121

Ya learn something new every day, Thank You.
and my gauge read zero, no pressure.

On my 1998 Camaro Z28 with the LS1 engine my OPSU broke and I had to remove the intake manifold to replace the sender, took a little while but not too bad.

On my 1995 LT1 the sender it was on the side on the engine I believe and had to remove NOTHING to get to it.

So the final conclusion here is that GM placing the OPSU in the back of the engine where no one can easily get to it in 1998 was a mistake and continuing to do so thru their model lines is just a pure act of stupidity on their part.

I like the idea of cutting a hole in the cowl, not sure if I will go that route but a thanx to all for Helping me to get a clear understanding of the situation and all of my options.

R&L's C6

[QUOTE=Batman75;1597235295]

My LS3 always ran low 20's when hot idle, around thirty driving down the road.

1bdvet

My sending unit has failed, oil pressure reads 80 on the gauge and since the engine hasn't failed, leaving it alone.

farmington

I've seen it all now, LOL.

WW7

[QUOTE=R&L's C6;1597236669]I agree, my oil pressure has alway been in the 24 to 26 lb range at idle when the engine is fully warmed up and the oil temp is 208 to 210 F. I know quite a few guys with a C6 that have the same pressures..As long as the oil pressure rises when the rpms go up your fine....WW

ls1121

I've read about people cutting a hole in the cowl to get at the OPSU. I cannot find any threads on how to actually do this, can anyone guide me these threads?

wayback

If you do change it I recommend Amazon, as they sell a solid brass unit.... do not recommended a stamped metal one.

Also you will need a thin walled socket. Auto stores sell one made just for OPSU.

I cut a hole to get to mine. Used aluminum duct tape to cover the hole (It can't be seen anyway).

ls1121

I guess the Important question is exactly where do you cut the hole?

I cut a hole once before, in my Camaro, to remove the fuel pump. I have no issue whatsoever with cutting a hole in my Corvette after all it is mine and paid for.

wayback

First disconnect the windshield washer hoses. Then remove the wiper arms and hood to cowl gasket...it just pulls off.

There is a screw on each side holding the cowl down, remove them and pull the cowl away from front qtr and away from the windshield and remove. There are clips that slide under the windshield.
OPSU is on drivers side behind the intake manifold.

Dano posted a pic in this thread. I used a dremel cutoff wheel and utility knife.

wayback

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Standard Motor Products PS308T Oil Pressure Switch