Changing an oxygen sensor

Friday, July 25, 2003

Dear Tom and Ray: This morning I went to my car to find that it had grown what appeared to be "hair" from the tailpipe. It was about 10 inches long and gray, with brown highlights. I had to get to class for a test, so I gave my car a haircut with my Swiss army knife. I tried to pull the rest out of the tailpipe, but it wouldn't budge. I am continuing to drive my car. What came out of the back end of my car? Should I get it checked? Any advice on how to tell a mechanic about this without sounding like I've lost my mind?Samantha

Ray: Well, Samantha, the first thing I'd do is contact Sy Sperling at the Hair Club for Men to see about becoming a supplier. If this continues, you could pay off your student loans, and then some.

Tom: We've actually seen this before, Samantha. It's muffler hair. Some cars (we've seen it on Hondas) use a fibrous insulating material as a sound deadener in their mufflers. When the muffler starts to deteriorate, the stuff starts to come off, and it heads out through the tailpipe. And you're right -- it looks and feels just like hair. I find it quite disgusting and creepy, actually.

Ray: What it's made of, I don't know. But now that you mention it, I have seen a large fleet of Accords in the Hair Club for Men parking lot.

Tom: So, what to do? In the short run, I'd apply some leave-in conditioner. That'll make it more manageable.

Ray: Actually, you can keep driving the car, but this means that your muffler is on the way out. And sooner rather than later, the car is going to get real loud. So if you've got the money, you might as well replace the muffler now, Samantha.

Dear Tom and Ray: My 1995 Honda Civic has been diagnosed with a bad oxygen sensor. Although I am not mechanically inclined and have almost no tools to speak of, I've been entertaining the idea of replacing the little sucker myself. Short of providing entertainment for my neighbors, is it a reasonable thing to do? Or should I sell biscotti at the local farmer's market instead until I raise the $211 it would cost to have it done by a pro?


Tom: Well, if you had to pick a job to start with, this would be a pretty good one, Leonardo. It's really fairly easy, on this car.

Ray: The oxygen sensor is right up front, just behind the radiator. You'll find the sensor threaded into the exhaust manifold, and there will be one wire coming out of it. Unplug the wire, and then -- using a 7/8ths wrench -- loosen up the sensor, unscrew it and remove it.

Tom: Then, in the opposite order, put the new one in and reattach the wire. If your check-engine light is on because of your bad oxygen sensor, it'll reset itself and go out after a while. That's all there is to it, Leo.

Ray: However, if any of the following situations occur, you should fall back to plan B ("B" for "biscotti sales"): (1) You are unable to open the hood. (2) You are unable to find or identify the oxygen sensor. (3) You are unable to remove the wire. (4) You are unable to loosen the sensor. (5) You strip the sensor because you didn't use a 7/8ths wrench, like we told you to. (6) The wrench slips and you bust a hole in the radiator while trying to loosen the nut.

Tom: But nothing ventured, nothing gained -- right, Leonardo? We'll be pulling for you, buddy.

"Car Talk" can be heard at 9 a.m. Saturdays and 5 p.m. Sundays on KRCU 90.9 FM -- Southeast Public Radio. Write to Tom and Ray at Car Talk Plaza, Box 3500 Harvard Square, Cambridge, Mass., 02238. Or e-mail them at the Car Talk section of

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