Friend's 99-320E with six cylinder, 85,000 miles needs a quart of oil every 800 miles. It also appears to have evidence of blow-by under the oil filler cap. He's had the car for a few years (since 25,000 miles), has all recommended work done at the dealer (including oil changes). Is this a problem or is it just a characteristic of the vehicle. If not can anyone give me any idea about the costs to correct his problem(s). I'll greatly appreciate any feed back that anyone can offer.