Dear Tom and Ray:

We recently purchased a 1991 Chevy Lumina with automatic transmission from
a friend. According to him, the car has always used oil. Currently at
72,500 miles, it requires about half a quart every 1,000 miles. The car has
always had oil changes every 3,500 miles. The car doesn't leak a drop, even
when parked for a couple of days. There is no noticeable smoke coming from
the tail pipe. It runs smoothly. Should I be worried about the Lumina's
"disappearing oil trick," or should I just keep buying oil on sale? --
Larry

RAY: I wouldn't be concerned, Larry. A lot of cars burn some amount of oil.
And in fact, we've heard that some manufacturers are telling customers that
it is acceptable for their new cars to burn a quart of oil in 750 miles!
Why are they telling customers that?

TOM: Because they've discovered that some of their new cars are burning a
quart of oil every 750 miles!

RAY: Why do new cars burn oil? Engines do run hotter these days, which
probably accounts for some of the extra oil burning. Plus, most
manufacturers now call for lighter grade of oil, 5W30, which may also have
an effect. Then there's the question of how well the car was broken in by
the owner, and whether someone at the factory forgot to put rings on all
the pistons that day.

TOM: And there's a great difference of opinion as to what is an acceptable
amount of oil to be burning in a new car. Personally, I think none is the
right amount.

RAY: And in my -- better educated -- opinion, given all the variables, I'd
say a quart every 1,000 miles is an amount you may just have to live with.
But if my new car burned any more than a quart every 1,000 miles, I think
I'd be steamed.

TOM: In an older car, it's more just a question of what you're willing to
tolerate, and how long you plan to keep the thing. When you start burning a
quart every 500 miles, then a quart every 400 miles, then every 300 miles,
at what point does it become such a pain in the neck that you decide to
either fix the car or get rid of it?

RAY: This decision may also be affected by how many neighbors direct rude
hand gestures at you in the morning while you're warming up your car, as
plumes of blue smoke waft into their kitchen windows.

TOM: And by how many times you're listed as Public Enemy No.1 by the local
chapter of The Sierra Club.

RAY: But I'd say you're nowhere near that type of life-or-death decision
yet, Larry. You say this car has always burned a little oil. And as long as
it's not getting worse, half a quart every 1,000 miles is really nothing to
worry about.

TOM: Just remember to keep your eye on it and don't let it run low. If you
do that, then it WILL be decision time pretty soon. Good luck.