Camry's are notorious for carbon build-up on their valve stems as they age.

Dear Car Talk

Dear Car Talk | Mar 01, 1998

Dear Tom and Ray:

We own a 1988 Toyota Camry four-cylinder with a stick shift and 140,000 miles.
Whenever we attempt to pass another vehicle, particularly on a hill or a curve,
we lose power and have to relinquish our position and glide sheepishly over to
the shoulder -- while noting an extended single digit through the rear window of
the unpassed car as it speeds ahead. This is not only humiliating but also
possibly dangerous.
We had the car "diagnosed" at the Toyota dealer and were told we needed a valve
job. We then took the car to our local mechanic who checked the compression,
said it was OK, and because of that, said he didn't think the valves were the
problem. He thinks it might be a plugged exhaust or catalytic converter. So we
took the car to an exhaust specialist, who said it wasn't the exhaust or the
converter. Now where do we stand? -- Robert

RAY: Where do you stand? In front of the service manager at the Toyota
dealership with your credit card outstretched.

TOM: Your exhaust guy has ruled out a plugged exhaust system. And while it could
be a bad fuel filter or fuel pump (and those are worth checking), I suspect that
the Toyota dealer will be proven right.

RAY: Camrys are known for having carbon deposits build up on their valve stems
when they get old. After the car has been running for a while, typically on the
highway or on hills, the carbon deposits heat up and expand. And when they
expand, they prevent the valves from closing all the way.

TOM: And when the valves don't close, you get lousy compression and no power.
But since this only happens when the engine is hot, it's not surprising that
your mechanic was confused by the dealer's call for a "valve job." In almost all
other cases, a car that needs a valve job will have bad compression and run
poorly all the time.

RAY: Sometimes on Camrys we've been able to clean off the valves by adding a de-
carbonizing fluid to the gas tank, like Chevron Techron or B&G 44K. But when
that doesn't work (which it probably won't with 140K on the engine), the next
step is a valve job, Robert. Good luck.

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One