2007 Chevy issues

[Preacherman]

My nephew bought a 2007 Chevy extended cab w/either the 4.8 or 5.3 (I haven't looked yet). It has 175k miles on it and has low oil pressure. He has replaced the oil pump and the oil pressure sending unit and it did not fix the pressure. Also when he changed the oil it was pretty thick w/some sludge. My guess is that the sludge has clogged the oil guides (or whatever they are called.) What say you gearheads?

 

[trekrok]

Has he connected a mechanical gauge to verify that the pressure is actually low? That would be my first step.

 

[918evo]

I will look at the datastream and see what the sensor is reading. The cluster stepper motors fail on the 03-07 Silverado. I would also take the oil sensor out and clean out the oil port with a wire or something. Those can get gunked up and cause sensor issues. Those clusters get swapped all the time and are very easy to manipulate, so it may be higher mileage(250K+). If it has high miles, excessive clearances can cause low pressure- I shim the pumps to get a bit more out of them. The most common causes I see are stepper motors and oil pickup tube o ring failure.

 

[Profreedomokie]

Maybe too much bearing clearance .

 

[Preacherman]

Thank you guys. Everything sounds easy to check except bearing clearance.

 

[Gunblinder]

It might just be this screen/filter

 

[Preacherman]

Update: My nephew advised that the pressure starts out normal but then when driving down the road it gradually drops and stays low.

 

[Mack45]

Sounds like the stepper motor on the dash gauge. I would verify actual pressure with a mechanical gauge as mentioned earlier.

 

[Preacherman]

Sounds like the stepper motor on the dash gauge. I would verify actual pressure with a mechanical gauge as mentioned earlier.

Thank you. After the great advise from you guys that's what it sounds like to me. It sounds like it loses voltage to the stepper motor.

 

[O4L]

Back in the old days depending on the type of oil and the miles on the engine, it wasn't all that uncommon for the oil pressure to drop some when everything warmed up and it would rise with the rpms. It was my understanding that as long as you had ten pounds of pressure for every 1000 rpms you were okay.

I don't know if that holds true with these newer rigs though because I've never owned anything newer than a 2003 and it held good oil pressure.