Is a cylinder losing compression a death sentence for this Mitsubishi?

Dear Car Talk

Dear Car Talk | Dec 01, 1998

Dear Tom and Ray:

I have a 1992 Mitsubishi Diamante with 144,000 miles on it. It is a car my wife
and I both enjoy. Recently, we had it serviced at a Mitsubishi dealership and
were informed that one cylinder had lost compression (down to 75 psi).
Apparently, for a car, this is like being given a death sentence. It still
drives just fine, but the dealer says a new engine will cost $6,900! Here are my
questions: Is this really the end for the car? Is this a mileage at which such a
problem is likely? Are there other options? -- Bob

TOM: The answers to your questions are yes, yes and yes.

RAY: The good news is that if it still drives "just fine," then it's only the
beginning of the end. And no further harm will be done by continuing to drive
it. Eventually, however -- probably months from now -- it'll start to run rough,
lose power and generally impersonate my brother's '63 Dodge Dart. But until
then, you can keep driving it.

TOM: And you shouldn't feel too bad, because you got almost 150,000 miles out of
this engine. And that's very good.

RAY: Your options, at this point, are 1) a new car, 2) a new engine, 3)
rebuilding the engine, or 4) a used engine.

TOM: I'd be reluctant to recommend a new engine or a rebuild. Putting $6,900
worth of new engine into a car in which every other part has 144,000 miles on it
is not a wise investment. A new engine will presumably last another 144,000
miles, while the rest of the car certainly will not.

RAY: A rebuild on this car will cost you less -- probably more like $4,000 --
but that's still an awful lot of money and leaves you with a better engine than
you need on such an old car.

TOM: The used engine is my choice. A dealership probably won't help you with
this, but an independent mechanic will. If you can locate a Diamante engine at a
junkyard in a car that died of non-natural causes (like a collision), you might
be able to pick up an engine with half as many miles as the one you've got. And
that would probably cost you between $2,000 and $3,000 installed, which is
getting much more reasonable, no?

RAY: Of course, when you buy a used engine, you're taking a chance that
something could go wrong with it, too. But if your mechanic checks out the
basics (like the compression and oil pressure) before he installs it, or buys it
from a reputable junkyard that warranties the engine and the labor, you should
be able to count on getting at least a few more years out of the car.

TOM: Before you go that route, however, have your mechanic check out your
Diamante from stem to stern, to let you know if any other significant parts are
about to fail. You wouldn't want to invest $2,000 in this car, for instance, and
then find out that you need to drop another $1,500 on a transmission.

RAY: Alternatively, you can simply drive this car until the compression problem
starts to bother you. And if you're lucky, that won't be until after you've
visited every single dealership on your new-car wish list.

* * *

Wait! Before you buy a car, make sure you read Tom and Ray's guide, "How to Buy
a Great Used Car: Things Detroit and Tokyo Don't Want You to Know." Send $3 and
a stamped (55 cents), self-addressed, No. 10 envelope to Used Car, PO Box 6420,
Riverton, NJ 08077-6420.

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One