Low Oil Pressure ,Next Step

[strutaeng]

"It's probably your bearing clearances then." I agree and yes I still have the AFM stuff

I ask because I thought the AFM required higher oil pressure to work properly? I'm only familiar with the Gen III, not much on the Gen IV+.

I ran the 4.3 in my 99 Silverado for 10,000 miles with low oil pressure before I retired the engine. It had about 5 psi at summer hot idle checked with a mechanical guage when I started getting low oil pressure. My dash guage was below zero and the check gauges light came on at stoplights. I switched to 50 grade oil and pressure improved to around 8 psi and I kept running because I didn't have the money for another vehicle or engine then. I never got any knocking and engine still ran fine when I pulled it.

I did teardown the engine because I was curious. Rod, main and camshaft bearings had heavy wear. Measured 4-5 thousands clearance on main and rods. The pump was actually the one with minimal wear.

So except for the AFM lifter actuation (or however they work?), the engine may still run good with that oil pressure for a while if you don't have any knocking.

Next step: What are your capabilities mechanically, knowledge is and budget? Tools, time and space? That will dictate if you rebuild it yourself, have someone rebuild it, junkyard swap, crate engine, etc.

 

[Hoeston]

Hows she running now?

 

[Hoeston]

I recently changed my oil pressure sensor and the filter.
The check engine light had come on and oil pressure gauge stuck at max 80. 3 codes for the sensor failure.
Prior to changing the sensor/filter the gauge would idle around 30-35 when warm, closer to 40 when cold.
Now, after changing them, the gauge looks like 23-27 when warm, 36-40 cold.

Been wondering if this is the start of losing pressure

 

[Dustin Jackson]

@Hoeston Those sensors aren't calibrated for scientific accuracy so there will be variations between what the sensor reads, especially if going with non-factory oil pressure sensor

 

[j91z28d1]

I'd have to look it up again but the factory manual calls out low oil pressure something like 7psi hot idle. if you're at 20psi up to temp and idling at 600rpm you're doing better than most.

edit* plus all the dash gauges are kinda general. you really need a scanner to read the oil pressure as closely as you're trying to.

the water temp on the gauge center can be as much as 20deg different too and still show middle dash.