Author Topic: Exhaust soot- what does it mean?  (Read 14992 times)

knockmacool

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Exhaust soot- what does it mean?
« on: October 12, 2009, 19:31:56 »
I did some work today on tracing the water in my "rear" footwell, which better acquainted me with my 230sl. I had never noticed I was missing one of the large soft top springs (cracked front eyehole where spring should go).
More importantly, after finished putting parcel shelf back in, started the car up, blipped it to 3500 rpms (something I don't usually do) and drove short distance to garage. When I stepped out to open the doors. I noticed exhaust was spewing wet soot, which settles as 1mm spots on gravel. Drove in and switched off engine.

I am not mechanically inclined, but this background might be relevant.
1. Car off road for extended period (15 plus years)
2. Car put back together by good mechanic, who did 600 miles before handover
3. Done 3.5k miles since
4. After my first 500 miles noticed no oil in fuel injection pump. Filled and has maintained level since
5. May have inadvertently richened fuel mix when looking for FI dipstick
6. Changed oil at 3k, did see that filter had suffered an "impact". I assumed a "plug" of oil had hit oil filter as we didn't find anything else
7. Car doesn't really use oil.   
8. Car has idled unevenly, but never stalled. With one exception, it has always started right up
9. Did notice small fume leak from exhaust previously
10. Under very heavy acceleration it will spew some black smoke

So my questions are what is the wet exhaust soot symptomatic of, and what should I do next? I have read a few threads, including http://www.sl113.org/forums/index.php?topic=1113.msg5454#msg5454
 but can't really sort what is relevant. I am always amazed how people on this forum can guide each other to a conclusion, hence my posting. Appreciate any suggestions.

Drew
 

thelews

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Re: Exhaust soot- what does it mean?
« Reply #1 on: October 13, 2009, 00:13:19 »
Probably symptomatic of not driving it enough to get hot enough to burn off the water in the exhaust.  Mix it in with the usual soot in the exhaust system and you've got wet black spray coming out the pipes.  Take her for a good long ride at higher rpms to burn off the water (condensation).  BTW, not driving the car until good and warm will create more condensation in the exhaust.  Eventually, the muffler will rust out.  Ever notice how your exhaust steams on a cold morning?
Enjoy some pictures at this link:
http://www.flickr.com/photos/8292359@N06/sets/72157603240571101/show/

John - Wisconsin
1967 Early 250 SL Red/Caviar, Manual #1543
1961 190 SL 23K miles
1964 Porsche 356
1970 Porsche 911E
1991 BMW 318is
1966 Jaguar XKE
1971 Alfa Romeo GTV 1750

J. Huber

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Re: Exhaust soot- what does it mean?
« Reply #2 on: October 13, 2009, 00:28:13 »
I think it sounds pretty normal to me. As John said, condensation and some exhaust soot will combine to make a mess of the area behind the pipes. Mine does it -- and has for a long time, generally only when cold though. The one thing you listed that I would consider an issue is number 10. If you take the car out and run it aggressively, that stuff should stop spewing out. Otherwise, I'd look at things a little closer. Valves or exhaust system? just guessing.
James
63 230SL

SteveK

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Re: Exhaust soot- what does it mean?
« Reply #3 on: October 13, 2009, 01:04:25 »
I would say a good Italian Tune-Up and then a 30 min run at 70MPH is in order.

w113dude

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Re: Exhaust soot- what does it mean?
« Reply #4 on: October 13, 2009, 12:19:58 »
Drew,

I agree with the first post, It is condensation coming out of the tail pipes, The very same thing is happening to my car, infact so much so that the muffler is rusted due to car sitting around not being used for years. Drive hard & long and you'll see it go away.

Shaun

knockmacool

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Re: Exhaust soot- what does it mean?
« Reply #5 on: October 13, 2009, 12:42:32 »
OK, will assume its exhaust related issue and drive it at slightly irresponsible speeds. Speed limit is 100km/h and 120km/h on the motorway.  The closest motorway is 45mins away and doesn't go anywhere I wanna go (Dublin  :o).  Thank you all for advice!

Drew

thelews

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Re: Exhaust soot- what does it mean?
« Reply #6 on: October 13, 2009, 14:27:57 »
OK, will assume its exhaust related issue and drive it at slightly irresponsible speeds. Speed limit is 100km/h and 120km/h on the motorway.  The closest motorway is 45mins away and doesn't go anywhere I wanna go (Dublin  :o).  Thank you all for advice!

Drew

We like to throw the speed part in because it's fun.  At the limits you mention, 100km/h, it's fine.  It's more the length of time you drive, allowing the car to fully warm up and burn off condensation.  Short trips without the car fully warming is the killer, as well as starting and not driving.
Enjoy some pictures at this link:
http://www.flickr.com/photos/8292359@N06/sets/72157603240571101/show/

John - Wisconsin
1967 Early 250 SL Red/Caviar, Manual #1543
1961 190 SL 23K miles
1964 Porsche 356
1970 Porsche 911E
1991 BMW 318is
1966 Jaguar XKE
1971 Alfa Romeo GTV 1750