Quote:
Originally Posted by plthijinx
no, that was the first one. this engine, er exhaust system has the manifold and cat's as one piece so to change the cats you in turn have to remove the manifold.
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But is that pictured oxygen sensor the one normally located (on most cars) only six inches from the engine block? Meaning of the word 'first' is not clear.
Are there two (the picture only shows one) sensors - each one for three cylinders? Of course another two sensors are after catalytic converters. Those would be reporting a failure. A report that implies those 'after' sensors are 100% OK.
A torch should be sufficient to remove most 'decade rusted' parts. Especially any oxygen sensor mounted on that stainless steel exhaust pipe. But if overheating due to excessive gasoline, then removing a part (ie oxygen sensor) would be difficult.
Implied: catalytic converters damaged and now seized by an engine always dumping excessive gasoline into the converters - as discussed earlier. Diminished (not yet failed) converters may be a symptom of a long existing problem that also caused lower gas mileage.
Federal law says an exhaust manifold must not fail for first 100,000 miles. Which is why most pipes are good for less than 200,000 miles. That pipe and cat converters typically do not fail. Says why those parts are so expensive. Parts that don't fail often have highest profit margins. We used to charge a 100% markup.
So, if an oxygen sensor is the first (my original question), then doing anything to replace it (soak it repeatedly in WD-40 for 24 hours before using the torch to heat it while using a socket wrench to remove it) is a best shotgun solution.
BTW, never saw a reverse threaded oxygen sensor. If reverse threaded, then a shop manual was blunt about that unusual threading.
Spending another $25 for the Car Chip Pro would have said much more. But if any part is to be replaced, a most suspect part is probably that 'first' oxygen sensor. Not any sensors after the cat converters. Replacing only that sensor is by far the least expensive of all 'shotgun' options.