If I can't find an oil leak and I don't see smoke, where is all the oil going?

Dear Car Talk

Dear Car Talk | Mar 01, 1999

Dear Tom and Ray:

My daughter's '89 Honda Civic with 100,000 miles on it suddenly started using up
to two quarts of oil per week. Sometimes more. It does not leak oil onto the
ground. It does not smoke at all. It still gets 40 mpg. We're at the point where
we stop at the gas station and say, "Fill the oil and check the gas." Where is
all the oil going? -- Larry

RAY: It's probably wafting into the wild, blue yonder, Larry.

TOM: While I can't absolutely rule out a leak, the only leak I can think of that
you might not notice would be a bad oil pressure switch. They tend to leak only
when the car is running. And if that were the case, the oil you're losing could
be scattered -- drop by drop -- all over town. But it's much more likely that
you're burning the stuff.

RAY: I know you think it's not smoking, but our vast (or at least half-vast)
experience tells us that if it's not leaking, it's burning. In fact, if you're
going through two quarts a week, a good mechanic can probably smell the burning
oil in the exhaust.

TOM: For a few minutes at least, until he keels over and passes out.

RAY: If it really started burning this much oil suddenly, I'd be willing to bet
that the engine overheated, and the rings got fried. Ask your daughter if she
remembers seeing the temperature gauge hovering in the hot zone recently.

TOM: At this point, you don't have much to lose by trying a few cheap remedies.
You can try using 20W50 motor oil and see if that reduces the consumption to more
acceptable levels. You can try an additive called "Restore," which occasionally
shows good results. Then you can try prayer, voodoo and wishing on falling stars.

RAY: And when all that fails, you'll need to rebuild or replace this engine, or
shop for another car. Good luck, Larry.

?(C) 1999 by Tom and Ray Magliozzi and Doug Berman
Distributed by King Features Syndicate, Inc.

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