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Discussion Starter · #1 ·
My exhaust tail pipe is covered in black soot. I have read that this could be due to a car runing too rich? That may be the case with a fault o2 sensor I believe...but I get great gas mileage, around 35mpg regularly, and would not think that a car runing too rich would get 35mpg. Would there be something else wrong with my car to produce the black soot? I don't race and I don't ever see black smog coming out of the tail pipe.
 

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If you are burning oil you will get some soot.
 

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Discussion Starter · #3 ·
I have a slight oil leak by my distributor. I am going to change my pcv valve and breather filter when I get home cause my breather is filled with oil which means my pcv valve is probably blocked and I might be burning some oil do to that, does that make any sense?
 

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If your PCV is stuck open you probably will burn more oil then normal.
 

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Discussion Starter · #5 ·
I doubt the pcv valve has ever been changed, it hasn't been changed in the 40,000 miles I've owned it for anyways. I only lose about .5 qts every oil change which is fairly good for a car with 142,000 miles on it.
 

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Black soot it normal. When fossil fuels are burned CO2 is produced. Through a complex series of reactions, soot and other stuff are produced. Over time your exhaust will become quite black. Burning oil will speed this process up. Keep in mind that other debris can sometimes get cooked inside your tailpipe. I frequnetly end up blasting blackened poplar fluff out the back end.

-Nick
 
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