Black Exhaust

[glchwalter]

I,m new to this forum and have a question. I have a 2010 silverado LTZ, crew cab short box, lazer blue limited edition, 5.3, 6 speed auto, 3.08 rear gear and 20" tires. My exhaust is very black with black liquid running out onto the chrome extension, 4400 miles on truck, not using oil. This is after a 3000 mile from Michigan to Florida and back, about 18 MPG running 70-75 mph. Dealer has no idea why, no codes, everything shows normal. Any one have any ideas? Dealer is still looking into it. My last 2 chevys were diesel 02 and 07, and the exhaust was not this black. RETLAW

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If it's getting 18mpg and not using oil, I say let it be. But, once in a while you gotta put the hammer down to blow the carbon out of it, also. All gas engines make carbon dioxide and water, but most will evaporate the water before it comes out the tailpipe.

[minibike132]

If it's getting 18mpg and not using oil, I say let it be. But, once in a while you gotta put the hammer down to blow the carbon out of it, also. All gas engines make carbon dioxide and water, but most will evaporate the water before it comes out the tailpipe.

 

Agree

[Silverado4x4]

Yeah dont worry about it, water comes out the pipe with the carbon from inside the pipes and gets on the tips, I have little black spots on my driveway from this.

[RayGMC]

If you run higher octane gas it will create more carbon build up. My Denali runs 93 and my tips are always black. The lower octanes do it too just not as bad.

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If you run higher octane gas it will create more carbon build up. My Denali runs 93 and my tips are always black. The lower octanes do it too just not as bad.

 

Very good point, didn't think of that. If you're not tuned for 93, DON'T run it!

[glchwalter]

If you run higher octane gas it will create more carbon build up. My Denali runs 93 and my tips are always black. The lower octanes do it too just not as bad.

 

Very good point, didn't think of that. If you're not tuned for 93, DON'T run it!

 

[glchwalter]

Truck is all stock and I run 87 octane. I wouldn't think running at 70-75 mph for almost 3000 miles I would have carbon build up. Yes the RPM's are low with the 3.08 gear but still I would expect to see a clean exhaust.

[AThomas7782]

I asked this awhile back. Apparently there's no such thing as a clean tailpipe anymore. I suspect the ethanol may have something to do with the carbon too.

[RyanbabZ71]

I asked this awhile back. Apparently there's no such thing as a clean tailpipe anymore. I suspect the ethanol may have something to do with the carbon too.

 

Running E85 (pretty much since new) my tailpipe stays much cleaner than my old 2000. When I would start my old truck I would get black junk all over my wall in the garage, with the new truck I get none of that. Guess E85 is cleaner

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There's no doubt E85 burns cleaner. Just the gas mileage is horrible and usually, IMO, is not worth the lower price.

[AThomas7782]

I asked this awhile back. Apparently there's no such thing as a clean tailpipe anymore. I suspect the ethanol may have something to do with the carbon too.

 

Running E85 (pretty much since new) my tailpipe stays much cleaner than my old 2000. When I would start my old truck I would get black junk all over my wall in the garage, with the new truck I get none of that. Guess E85 is cleaner

 

I wonder if in a non-FlexFuel vehicle that the ethanol messes with the air/fuel mixture enough to cause soot? I'm just grabbing at straws at this point.

[RyanbabZ71]

Just the gas mileage is horrible and usually, IMO, is not worth the lower price.

 

Thats why you do a cost/benefit analysis. So far at $1.99 a gallon running E85 in my truck or Tahoe (even with the lower mpg, 10-15%) is worth running it. I have been running it 100% since January.

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Just the gas mileage is horrible and usually, IMO, is not worth the lower price.

 

Thats why you do a cost/benefit analysis. So far at $1.99 a gallon running E85 in my truck or Tahoe (even with the lower mpg, 10-15%) is worth running it. I have been running it 100% since January.

 

 

Yeah, we don't have any E85 places around here, so I don't know anyone who's been running it. So all I know is what's said about it on the internet. Thanks for expanding my knowledge of it, now I know it's worth it.

[fraiolib]

dealer told me when i bought my truck if E85 isnt a dollar or more cheaper its not worth running