question of where is my missing oil

[TDC240sxPunk]

Ok i'm having a dillema, every 3k miles i do an oil change and only about a quart or sometimes 2 of oil comes out. Iknow you're going to say i'm burning it or leaking. Well i'm not, no oil pools in the driveway or anywhere i park, no blue smoke coming out of the exhaust pipe. I'm baffled by this. Where is my oil going to. Has anyone ever had this problem.

my compression is right around 146-151 all the way across, no sperratic change in cylinder pressures from cylinder to cylinder.

and what's wierd is my oil light works but doesn't come on at this point, and my car runs fine without ticking or knocking.

Help...?

[szh]

Please pardon what may seem like dumb questions from me, but this is pretty unusual - you should get more oil out than that!

1. Before you remove the oil, does the dipstick show that the oil level is normal? Or is it down already before you drain?

2. Is this with or without a filter removal at the same time?

3. Is the oil cap off the engine when you drain?

4. When you re-fill after the change, does it take a normal amount of engine oil to get back to the correct level on the dipstick?

(I know, I know, silly questions, but I had to ask ... to eliminate all of the obvious possibilities!)

Z

[TDC240sxPunk]

1)nope, doesn't even register any oil at that low2)with removing the filter3)yes4)yes

[virus77]

well you should keep an eye on your oil in between oil changes since running a few quarts low can cause some serious damage and you know the car is consuming oil. Try putting in some "stop leak" on your next oil change and see what happens, if you are burning a small amount of oil you may not see it out your exhause but throught a 3000 mile span it will come out to be a few quarts.

[toki]

yeah, probably a bad valve seat or something, it burns too little to be detected at once, but its ALWAYS doing it, so it will add up eventually.

[szh]

1)nope, doesn't even register any oil at that low

As I read this answer (i.e., that the dipstick shows oil is low just before you change it), then I agree with the others. You are definitely burning oil (gradual enough that it does not show) or it is leaking somewhere.

I would not let the oil get that low between changes ... check it weekly and add oil to bring it back to "between the marks".

Separately, you need to figure out where it is being burned or leaking or something!

Z

[C-Kwik]

A leak down test will give you a lot of insight as to whether or not the combustion chamber is a problem. Pad piston ring sealing will not only allow excess oil to exist in the combustion chamber where it can be burned off, but also can allow excess blow-by to push an excessive amount oil mist out of the crankcase and into the intake via the PCV system. Minor losses in ring integrity can go unnoticed visually. Oil being burned in this manner will be relatively smal, but add up quickly over 3000 miles. Where you will start seeing smoke is when you get to half a quart or more per week as there would be many opportunities for oil to begin to pool up somewhere and be burned off in a big wiff leaving a momentary cloud of smoke. The leakdown will either expose or eliminate a lot of the possibilities quickly. Other sources are the valve stem seals as toki said or even turbo seals. Make sure you are not running too much oil pressure into the turbo as well.

In any case, check your oil level once a week to make sure you keep an adequate amount of oil. While the car certainly appears drivable, you don't want an engine failure to result.