The curious case of the missing oil.

[jwalker]

I have a 2004 Silverado 5.3. Since I purchased the vehicle, it has never used or leaked a drop of oil, ever. I've used AMSOIL Signature oil & WIX filters. About 6 months ago, my "low engine oil" alert came on in the D.I.C. I checked the oil & there was less than a quart showing on the stick.

 

I stopped at a place here that sells AMSOIL & put in 2 quarts there & had 2 in reserve. I went home & let the vehicle set for 4 hours, checked the oil, now It was 2 quarts over.

 

Fast forward to this past saturday, I checked the oil before heading to Chicago to have Justin at Blackbear do a tune for me. Why I checked it, as its never necessary, who knows. Again its showing just 1 quart. So, I put in two quarts and headed out, asuming the same thing happened again. Stopped 1/2 way to Chicago & checked the oil, sure enough, over 2 quarts. As a side note, the trip to Chicago & back yeilded constintaly good oil pressures, so clearly the oil is not over heating due to lack of oil / oil hiding in the heads.

 

Where is the oil hiding?

[newdude]

PCV system? Pull the air duct off the throttle body and crack open the body valve. Shine a flashlight in the intake and see how much oil you see puddled in there. The drivers valve cover if I recall has a redesign out with a new baffle for being over aggressive and sucking too much oil into the intake.

[jwalker]

Thank you for the quick response. If it is getting sucked into the intake, it would be getting burnt out through the engine, correct? The engine uses no oil however.

[Gun Designer]

How about slow drainback. Even though you use good oil, maybe the passages the oil passes back to the oil pan are clogged up. I one time pulled a valve cover off an older V6 and the oil pourd out of the cover. Also have seen them be plugged in the older V8 oil valley. Just a thought, not that certain about the 5.3's. Had one with 208K when I traded it and this one has 70K without ever using more than 1 qt between changes.

[Z45]

You have to be misreading the dipstick when you think its 2 qts low of it ends up being 2 qts over-full. If the oil is below the cross-hatched area on the dipstick you need to add 1 qt., not 2. To get an accurate reading you need to wait about 15-minutes so don't automatically dump in 2 qts when you are just guessing at how much you need to add. I have seen it before where someone added to much oil thinking it was real low when all they did was misjudge how low it really was.

[jwalker]

Definitely not misreading the dipstick. Thank you however for your response.

[scooby5121]

PCV system? Pull the air duct off the throttle body and crack open the body valve. Shine a flashlight in the intake and see how much oil you see puddled in there. The drivers valve cover if I recall has a redesign out with a new baffle for being over aggressive and sucking too much oil into the intake.

J Walker.... buddy here quotes that it is puddling in the top of the motor... Not going in the combustion chamber and burning.

On the top between the heads and valve assembly..

Scooby

[txab]

[txab]

I've got a question...... what did you do about being "2 qts" over the first time?

[jwalker]

After determining that the oil was never gone, I simply took the oil out by refilling up the empty quarts via the drain plug and dropped them off at the oil recycler here in my town. After that, the oil was at proper levels and all was good. There has been an oil change since then, and was filled to the proper levels as well.

 

 

I'm definatley going to check into getting a new PCV valve as that seems to be the easiest troubleshooting idea thus far. Hopefully, I dont have a blocked return in the intake area or heads.

 

Thanks again for everyones input.

[txab]

2004 has no PCV, it has a fixed orifice that requires no service. If it were a problem like a PCV, then your oil wouldn't magically re-appear later. It would be burned. I'd look into pulling valve covers and see what's going on there. Have you owned this vehicle from day 1 or did you buy used?

[jwalker]

Owned Since day one. The trip to Chicago I made this weekend was 4 hours there, 4 hours back. If the heads were loading up with oil, I'd imagine there would of been oil starvation at the crank due to the constant 2000 RPM's at 70 MPH for 4 hours or at least a noticable fluctuation of oil pressure due to a lack of oil or superheated oil breaking down. Neither were the case.

[newdude]

J Walker.... buddy here quotes that it is puddling in the top of the motor... Not going in the combustion chamber and burning.

On the top between the heads and valve assembly..

Scooby

 

The oil in the intake is straight up un-burnt no joke. You could pour it back into the motor. I have seen it before on both my 2004 and 2006 6.0 trucks I had.

[jwalker]

So the $64,000 question is, what in the intake is blocking the oil flow intermittently?

[txab]

So the $64,000 question is, what in the intake is blocking the oil flow intermittently?

Only places to "hide" are....

 

heads

 

valley pan area

 

Any oil that gets into the intake is not going back to the pan

 

 

No other magic places for it to hide. Unless you've got a magic unicorn engine.

 

If you have been running a good quality synthetic for a while, I'd find it hard to believe that you would have a sludging problem that would cause oil not to drain back.

 

I'm still trying to understand when it shows your a qt low, why you dump 2 qts in?? The whole dipstick only represents 2 qts at the most