Caution: Carbon monoxide may cause typos.

Dear Car Talk

Dear Car Talk | Apr 01, 1990

Dear Tom and Ray:

A couple of days ago while walking to my Camry, I noticed that the tail pipe was closed. Upon inspection, I found that it was full of dirt for some six inches. I don't know how long it had been plugged up, but I think it was at least a week. I would appreciate knowing what effects this can have on a car. Would it affect starting? Am I living on borrowed time because of carbon monoxide poisoning?

RAY: Judging from all of the typographical errors you made in your letter, I'd say the carbon monoxide has already gotten to you!

TOM: Actually, Bruce, carbon monoxide really is something for you to worry about, and here's why. Normally, when you plug up an exhaust pipe, the engine should stop running. If the exhaust gasses can't get out, the new fresh air and gasoline mixture can't come in. When that happens, combustion stops and the engine stalls.

RAY: The fact that your car continued to run for a week (or even a few minutes) with the tailpipe plugged up is bad news. It means that the exhaust IS escaping from somewhere other than the end of your tail pipe.

TOM: In fact, that's how mechanics test for exhaust leaks--by plugging up the exhaust pipe and seeing if the engine stalls. So my guess is that some five-year-old child prodigy mechanic decided to test for exhaust leaks by making mudpies in your tailpipe. He probably got called home for his nap before he had a chance to finish the job. You should get it fixed, Bruce, but don't let that kid work on it again.

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