[Jay H 237]

Beth, there's many possibilities.

It could be something major or minor or even several things adding up to cause this.
How much milage is on the car? Do you know which engine is in the car?

As Wayne asked, are you going by the light or dipstick?

If the light comes on but the oil level is OK (or near OK) on the dipstick then the possibilities are that the oil sender is/has failed, the wiring for the oil sender is damaged or a connection is loose, or you have low or high oil pressure. Low presure would mean either the engine is worn or the oil pump is failing. High presure is usually a restriction (clogged oil passage) in the motor.

Is the motor physically covered with oil?

You could have a clogged PCV and when the engine warms up and you're driving it's forcing the oil out of itself. The crankcase pressure is too high. Also check the air filter, it shouldn't be covered in oil. A PCV is an easy fix, you could do it yourself, and costs less than $5.

At the age of the car you could also have several gaskets that are dried out contributing to the loss of oil.

If you are in fact burning that much oil on a short trip then you would have very visible blue smoke from the exhaust (white smoke would be coolant).

And that brings me to my next question, how does the coolant look? Your car would use the standard green antifreeze and it should look that way, not dark colored and having oil in it. That would mean one of the internal gaskets has failed on the motor and they're mixing together.

One thing you can do is take it to a shop and ask them to preform a "leak down test". This is where they put a dye in the oil and see where it's going. This would cost under $100.

Beth, if you've been adding oil according to the light only and find out it's overfilled on the dipstick get it drained out and replaced immediantly. Overfilling a crankcase is very bad, the oil gets whipped into a useless froth when the engines running. The oil pump is supposed to deliver the oil to all internal parts of the engine, and the crank shaft and connecting rods aren't supposed to be submerged in the oil.

There's a few more possibiliteis I can think of but we really need to know whether you're going by the dipstick or light.

EDIT- You and others posted while I was typing up my answer. At 70k you shouldn't be going through that much oil.

Something else I just thought of and that I actually know of happening is using the wrong weight oil in the car. I don't know who changes the oil in your car but if they're using a lighter weight than recommended then it could be slipping past the rings and burning it.

I would go for the leak down test and also a compression test. With those two tests you will know the condition of the motor and what repairs it may be facing which you can use to decide whether to keep this car and repair it or unload it.