Adding 1qt/2K, ever need to change oil?

Well - if you plan to keep your car for a while, and if your goal is to minimize the total cost of ownership, then I would say you should replace the oil and oil filter now. Otherwise you may find that the engine will consume oil at an increasing rate as the internal parts continue to wear out due to insufficient lubrication - and eventually you may need to replace the engine.

I'm not sure how, by looking at the oil on the dipstick, you can say that the oil is 30% dirty vs. 100%. What constitutes 100%?

 

Not a good idea. Even though you're adding fresh oil every 2K miles, there is a risk that the oil filter will clog after a certain number of miles. If that happens, the bypass valve in the oil filter will open and you won't be filtering the oil at all.

Better to change the oil and oil filter at the recommended interval of 5000 miles (if you're using dino oil) than to flirt with disaster.

Engine oil, while no longer inexpensive (used to be on sale for 29 cents a quart not that long ago), is still cheaper than spending $$$$$$ rebuilding or replacing the engine.

 

Yes, continue replacing the oil and filter. You're leaking and/or burning oil and leaving the dirt in the engine.

 

That is one reason.

Another reason could be leaky valve stem seals, so engine oil leaks down from the valvetrain area into the cylinder combustion chamber.

 

167k miles and burns a quart every 2k miles.... The oil filter will still need changing but I would think you could increase your oil change interval since the fresh oil starts with no pollutants or metals thus lowering the overall trash in the oil.

Mine burns a quart every 5k. Makes me feel safe going to 15k with Mobil 1 EP and Mobil Filter. It basically gets a quart of fresh at 5k and 10k and a full change at 15k.

 

It is probably burning oil because of the buildup on the valves which allows oil to pass through and be burned off. A contributing factor in this is using oil well past its usefulness. The color of oil has nothing to do with how well it lubricates and protects. I would suggest changing your oil and filter every 5 k or risk changing your engine.

 

You really can't tell much of the oil's condition by looking at it. Sample it and send it off for testing. And change your oil regularly.

 

Well I have no technical knowledge but you have two ways to remove contaminants (1) via filter and (2) via oil removal. If you were using say Mobil-1 5W-30 my total inventory is only 3 quarts, so you are replacing 100% oil every 6000 miles. How about every 6000 miles replace filter (Mobil-1 filter). Common sense dictates this might work and basically using same amount of oil as no-leak case. As a minimum replace filter every 10000 miles (now please).

 

If not already been done I would recommend changing the PCV valve, Part of it's job is to reduce pressure in the crankcase. If the valve is not working properly it will cause a substantial increase in oil consumption.

 

I guess the simplest way to answer your question is thus: All oil whether conventional or synthetic has an additive package added to a base stock oil. These additive provide: viscosity, corrosion inhibiting, anti-oxidants, friction modifiers, anti wear additives, cleaning (detergents) and many other things. What goes bad in the oil is the additives which is exactly what protects the engine. The base oil is just a carrier for the additives. When you simply add a little oil to the old oil you give a little bump to the depleted additives but not nearly enough to protect the engine from damage and sludge buildup. The old oil has also lost ability to resist sticking to the engine parts.
The car burns oil because the lifters are loaded with carbon and the piston drain holes get clogged and the oil cannot drain into the crank case so it gets burned off.
This is what happens to an engine when it is not properly taken care of. You end with an engine that could easily go 300-400k miles that is trashed.

 

You have a car that in good shape is worth $6000 according to KBB. I am simply suggesting that you change the oil more frequently. Excess oil on the sides of the piston either drains back to the crank case through the holes in the piston or gets burned off creating a buildup on top of the piston. If the oil is old and dirty and doesn't have any additives left it will/can clog the drain holes so more and more oil is left on top of the piston to be burned off. A secondary effect of burning oil is that it can cause your O2 sensors and catalytic converters to go out and those are far from cheap.

 

You may want to try a different brand of oil . The change may help free up a few things. The pcv change may help as well.

 

It doesn't matter if you see where you are wrong, when your engine grenades itself and you're stuck with a very expensive paperweight.

Why must you fight common sense? You could ask 1,000 mechanics, and they'd all give you the same answer... you NEED to change your oil on a regular basis.

Ever heard the saying "penny wise, but pound foolish"?

 

The OP has a perfect right to ask for and be given a rational reason for changing the oil at the same interval regardless of how much extra oil is put in over the normal change period. And nobody has given a rational reason yet that I have seen. Saying that the "additives are bumped up a little when you add a quart of new oil" is a worthless statement, not rational. How much is the additives increased? How about at least 25%. Why doesn't the dirt and grime burn up along with the oil that is being burned in the combustion chamber? The problem here is that we have too many "experts" pontificating on a subject they have no expert information on. I know this because I've caught myself pontificating on electronic equipment repairs, that I have 40 years experience in, that in that instance I really didn't have any studies that I could refer to that I could back up my answers with. Can anybody come up with a study that has been done on this subject? Have you done your own study, showing additives being reduced to nothing, or dirt and grime increasing, even though you are adding oil to replace burned or leaked oil at 100% of the original amount, during the normal change interval?