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I have just begun driving my car. Once it warms up, there is an odor and smoke coming off of this black sleeve that is between the exhaust manifold and the catalytic converter. Is this a factory part or some sort of patch or add on? Maybe I just need to drive it until it burns off but that makes me nervous. Any ideas would be helpful. Wraithman?
 

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That is a stainless steel covering that is spot welded along the seams. There are several sections on the front part of the system before the cat. Often there is oil and drippings that run down the the exhaust and find there way in there. To make matters worse, there is a hi-temp insulation wrapped around the main pipe and the cladding is installed over it. This keeps the heat inside the pipe before it gets to the cat and also quiets the exhaust note.

Here is a pic of what is in there.
 

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Wraithman, I can not tell you how glad I am to have someone to go to with the knowledge base you have on my exact model. Thank you! Thank you! And Thank you!
Since the car has been driven very little it may have some built up oil in there. Should I just drive it until it burns out? Is there some other way to clean it out? What do you suggest?
 

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It is almost certainly oil. These cars are well known to leak oil from multiple locations, at least with the original seals. There's a reason that the old saw regarding Shadows, "If there isn't oil under it there isn't oil in it," came into existence.


That being said, one of the reasons that valve covers can leak is because the flame trap has never been cleaned out, causing excessive positive crankcase pressure. See the topic, Flame Trap on Oil Filler - The Need to Clean It.
 

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Unless you have the skills, a spot welder, etc to perform surgery on this, your only option is to let it burn off. It may take awhile and maybe embarrassing until it clears.
 

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I am thinking about spraying a non-flammable degreaser into it to see if I can wash some of it out. I am thinking Simple Green would do a good job. Would that help?
It is a little embarrassing and it smells up the garage when I get back from a ride.
 

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I'll go with Brian's theory of dripping oil. The other possibility is brake fluid. I had a slow leak on an accumulator on my car (now repaired) and it was dripping down onto the exhaust pipe causing smoke when the exhaust had heated up.



I think cleaning the section with simple green is a good idea but I would have thought any residual oil would have burned off by now, hence my thought that the oil/brake fluid on the exhaust pipe is being replenished each time you drive the car.
 

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I think cleaning the section with simple green is a good idea but I would have thought any residual oil would have burned off by now, hence my thought that the oil/brake fluid on the exhaust pipe is being replenished each time you drive the car.

Personally, I think using a degreaser is a complete waste of time, having been down this road in the past myself.


If you take the car out for a drive all residual oil should burn off in a very short time once the exhaust is up to temperature (or brake fluid, but given what you've said with regard to smell, I feel this less likely). If you are getting ongoing smoke there is either a reservoir of oil in a pipe wrap (which my cars do not have) or you are getting additional oil being added via drip as you drive (and SRH33576 did just that, even with new valve cover gaskets, and this resolved once the flame trap was cleaned). It was fascinating to eventually figure out the utterly circuitous route the oil was taking. It didn't drip straight down, but followed the engine contours and eventually dripped off.



There has got to be some semi-continuous source feed going on here.
 

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Trying to wash out the grease/oil/fluid that is sandwiched between the actual downpipe and stainless covering is fruitless. It will take alot of driving to "burn it off" due to the fact the fumes/smoke has a difficult time of escaping.

I would suggest you first find the source of the leak or drip, etc and then proceed to plan B.
 
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