Oil Change Oddity....Help

[BATOYGIO]

To keep it short, I changed my oil on jack stands yesterday and put in 8 quarts, yet only got out 6.5 quarts. I measured my oil level cold and its between the middle and top dot, closer to the top. Measured it hot and it is between the middle and top, closer to middle. Oil pressure at 19x F at idle is about 35, and when I get on it, its between 50 and 60. The level and pressure lead to normal readings but putting in and getting out such odd quantities has me worried. Any ideas?

[Eidolon]

Any idea what your oil level was before the change? Your pressure readings sounds about like what I get, perhaps a little higher. But you have AFM, so you need slightly higher pressure.

[joemac]

Did you check the oil fill throughout the last cycle to confirm it didn't need or consume any oil before the change? Was the car level on jack stands or was it higher front to back or side to side?

[BATOYGIO]

I had checked the oil at the previous change and it was good. Possibly lost a little through the 5k miles but I keep an eye on the pressure (Dashawk) and it never seemed too off...as for jack stands, I put a stands on the passenger side (since the plug is on the driver side) so that the oil drains better...but maybe that doesn't actually help? I also never did the rear main seal so maybe thats the culprit, but a quart and a half seems like a lot to lose through the rear main seal?

[TooManyHobbies]

I had checked the oil at the previous change and it was good. Possibly lost a little through the 5k miles but I keep an eye on the pressure (Dashawk) and it never seemed too off...as for jack stands, I put a stands on the passenger side (since the plug is on the driver side) so that the oil drains better...but maybe that doesn't actually help? I also never did the rear main seal so maybe thats the culprit, but a quart and a half seems like a lot to lose through the rear main seal?

You can lose/burn a lot of oil before it ever shows up on your oil pressure. I would start checking the dipstick more often.

[switchbladesilver09]

oil in oil filter?

[Seattle09GT]

Although highly unlikely, have you checked your coolant to make sure there is no oil in there. Dexcool + oil = foamy chocolate milk in the low pressure coolant tank.

[tchr49]

oil in oil filter?

No doubt you changed the filter also, but did you fill the filter with oil before installing it? Even though it appears to be a small filter, those little buggers will hold a surprising amount of oil.
Also helps to have oil in the filter before startup.

[BATOYGIO]

Yep filled filter with oil. Thanks for all the responses. I think the next change ill have it done on a lift and see what comes out then. I am thinking maybe there was oil left in the corner of the pan in front of the filter and behind the plug hole. Its not too bad for a little old oil to stay in there since there is so much new oil to mix with it right? Ill change in another 5000 and see what comes out on a perfectly level lift.

[Chewy]

A gal at work has a 5.3L TB that uses 5qts of oil every 1000 miles! NO SHIT! I've watched it when she starts and drives away and I see NO smoke burning. She says it's never left a puddle either.:uhm: It's not unheard of to use SOME oil. My G8 doesn't use nearly as much as you're seeing, but I drive 95% highway with it. I change the oil every 7500-9000 miles and use Mobil 1 extended.

Oh and I change mine on ramps...

[MeanGreenZ71]

GM has a certain amount of oil that they consider "normal" to be consumed in our engines....I just cant remember the exact number right now.

[WickedMom]

I believe the GM 'normal' consumption rate is 1qt for every 2k miles. IIRC.

[Napalm]

I had checked the oil at the previous change and it was good. Possibly lost a little through the 5k miles but I keep an eye on the pressure (Dashawk) and it never seemed too off...as for jack stands, I put a stands on the passenger side (since the plug is on the driver side) so that the oil drains better...but maybe that doesn't actually help? I also never did the rear main seal so maybe thats the culprit, but a quart and a half seems like a lot to lose through the rear main seal?

I don't know all your mods but I assume since you mentioned monitoring with a dash hawk you have a few.

1) 2 qts in 5K miles especially with some wot driving is not a lot of oil to push through a rear main seal. Infact I assume you check the spot in your garage floor often?
2) with your mods I assume you've done something different with the PCV system - catch can or you re worked it to dump off the back. That can account for quite a bit of oil. My catch can gets about 1/2 a quart between oil changes and I have a lightly modded motor with AFM active.
3) are you sure you put in all 9 quarts with the last oil change, (ok 8.5+ quarts)?

If you don't have major oil spot in garage floor, and you don't pour oil in it like pouring sand down a rat hole - then I would check the stick more often (every gas fill up) and watch it for a while.

Please report back.


GM has a certain amount of oil that they consider "normal" to be consumed in our engines....I just cant remember the exact number right now.

Its whatever number you quote X2 so the dealer doesn't have to actually agree to replace your engine under warranty. :boxing: