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Just what is that curious hole doing in Jeff's Camry's exhaust pipe?

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Dear Tom and Ray:



My wife has a 1994 Toyota Camry with a very loud exhaust. I figured there has to be a hole somewhere causing this. So, when I got home today, I started her car and could tell that the noise was coming from the front. As soon as I looked underneath, I could see a hole. It is well before the manifold, in plain view, and is located on the pipe. But it's not a rust hole or a crack; it looks like a hole that was intentionally put there. Then I immediately noticed, hanging right next to it, a small tube that looks like an exact fit for the hole. It is obvious that this tube is supposed to be connected to this pipe. What is it, and is it an easy fix? -- Jeff

RAY: Boy, you're really taxing the old brain cells by asking us to remember what the exhaust pipe on a '94 Camry looks like. Sure you don't want to quiz us on the Second Italo-Abyssinian War instead?

TOM: I think that hole was some kind of test port.

RAY: I think my brother's right. A lot of cars from that era had a tube in the engine compartment that plugged right into the exhaust pipe, before the catalytic converter. It allowed the mechanic to stick a probe into the tube and analyze the pre-converter exhaust.

TOM: Then he could compare that reading with the exhaust coming out the tailpipe -- on the other side of the converter -- and see how well the converter was working.

RAY: But that tube has now rusted off, and all you're left with is the hole. And since you really don't need the tube anymore, just have someone weld or braze the hole shut for you.

TOM: Or you can go with my brother's favorite exhaust repair product: frozen concentrated orange juice cans.

RAY: Nah, they haven't been the same since they switched over to cardboard. Too many fires! In any case, I wouldn't spend a lot of money on repairing it, because chances are good you're going to have to replace the whole exhaust system before long. If that connector has rusted off, chances are there's a lot more rust where that came from, Jeff. Good luck.
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