Hi, I recently drove my wife's 1998 V70 on a 1000 mile trip and had to fill up twice. In doing so I realized that it is burning about 1 quart of oil per tank of gas, or approximately 400 miles. This was very alarming as my 1999 S70 has is just now crossing the 350k point and burns almost no oil. The V70 is very high mileage as well and has almost 250,000 on it. It has been serviced regularly and oil changes are done with Mobil 1 synthetic 10W-30 every 5000 miles.

I've been searching the forums for cause and trying to determine how serious this is. According to what I've found, 1 liter per 1000 miles seems to be the acceptable rate of oil consumption which the car has far surpassed. However, I've found many differing responses here and in other forums that range from simply continuing to feed it oil to replacing the entire engine. If anyone could lay out some of the main possibilities for why this is happening and give me a better idea of how serious this is, it would be much appreciated.

Thanks,
Ryan