No oil on dipstick

[strutaeng]

Hey man, it happens. You likely still had oil BELOW the low oil indicator sensor.

On my old K3500 I once started getting this weird issue: when I took off, my oil pressure gauge dipped to zero momentarily, then came back up to normal. Truck doesn't get driven much at all.

One day I checked the oil, and didn't register anything! I added I can't remember how much and problem went away. I think what was happening is when I accelerated from a stop, the oil pickup tube saw little or no oil!

The truck does leak from several places. It's pretty grimey down there. In retrospect, I don't even know if that model even has an oil level indicator. I guess not?

My lesson learned if keep an eye on oil level on that vehicle...

 

[donjetman]

@Dustin Jackson
also, if you haven't installed the GM improved driverside valve cover, part # 12570427? that is where your oil is going.
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

 

[Dustin Jackson]

@donjetman I did install the new style a couple years ago when I did my AFM delete. After the AFM delete I had little to no oil loss/consumption… until now.

 

[Dustin Jackson]

Something else, I don’t think my Tahoe has an oil level sensor. I can see where one would go on the oil pan but there is just a metal plug in it instead. That sound right?

 

[Dustin Jackson]

Just crawled under the Tahoe and I do have some sort of oil leak. Thinking either oil pan gasket or front main seal. Oil filter is dry, oil cooler plate is dry, rear main seal area is dry.

Thoughts?

 

[Dustin Jackson]

@Marky Dissod Can you elaborate on the engine braking causing oil consumption thing?

It’s been a while since I made this post and so far there is no oil on the driveway or anything so I don’t think my Tahoe is leaking out all the oil so I’m wondering if you are right about the engine braking thing

 

[Marky Dissod]

Know for a fact I can tune old LT1s to consume more or less oil at my pleasure, from learned experience.
What I still don't get, is how and why.

Methinks, during NORMAL power strokes, explosions push oil away from combustion chambers,
and engine sucks external atmosphere easily enough.

During 'power' strokes with engine braking, additional vacuum drags oil toward combustion chambers,
either the short way, up the cylinder walls sneaking past the piston rings,
or the long way, sneaking into the intake through the PCV system,
because it's actually easier for the engine to suck on its own internal atmosphere than the tiny amount of air that manages to sneak past a closed throttle - mostly closed, in your case.

Someone, please, come along, feel free to make me look dumb, so long as we all learn something?

I actually wonder if engines are SUPPOSED to consume very small amounts of oil during engine braking?
As in, the alternative might be worse ... ?

 

[blondie70]

I think you are correct on this theory.

 

[Doubeleive]

@Marky Dissod Can you elaborate on the engine braking causing oil consumption thing?

It’s been a while since I made this post and so far there is no oil on the driveway or anything so I don’t think my Tahoe is leaking out all the oil so I’m wondering if you are right about the engine braking thing

that's not enough of a leak to loose 2qt's.

 

[Marky Dissod]

... not enough of a leak to lose 2qt's.

How many miles of engine braking are we talking here?