4.8 vortec sooty exhaust

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My buddies 2011 Chevy 1500, which was bought brand new and has never towed a day in its life, all easy highway miles. 120, 219 miles total and 5,750 miles on the Castrol Edge HM 10W30 and Fram XG filter which was drained today and replaced with Supertech Dexos 5W30 and a Baldwin filter. I always noticed the tailpipe was sooty, but never really gave it a close look until today. The inside of the tailpipe has a good buildup of soot, and the underside also. I cut open the Fram XG filter, no gunk or sludge at all inside but the filter element was extremely black for 5,750 miles. Should the tailpipe or filter element be any cause for concern? Any of you with vortecs notice this also? What mileage should the spark plugs be changed in these engines? Besides the sooty exhaust, the truck still runs great and gets great mileage, has never had any problems or any CELs come on in 120k miles.
 
All those easy miles never got it hot enough to blow the soot out. Italian tune up time
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I have a 06 6.0 vortec w/138k. The tailpipe is spotless. No soot at all, burns less than 1/2 qt per +-6500 OLM OCI. Other vehicles I've owned, especially Toyota's that combust more oil have sooty tailpipes. I don't think that running rich alone causes the soot. I think its oil consumption thats mostly responsible

Edit: Says 4.8 right in the title, disregard that question
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I had an 04 silverado w a 4.8l. I used many different brands of oil (syn blend mostly) and the exhaust wasn't as sooty as any other normal vehicle. My wife's BMW tail pipe is actually more sooty. Perhaps it's more related to fuel than oil? IDK
 
Not really pertinent to the OP's question, but along the same lines something I have wondered about. I know that manny manny years ago, if looking at a used car, you would look at the tailpipe, and if it was white, you could be pretty sure it wasn't an oil burner, and if black, either it burned oil, or it was burning excess gas, which could be cold weather short trips with the choke on most of the time. But NOW, it seems all the cars, always have black tailpipes, even though they burn much less gas and oil than back then. WHY? Is it the gas of today, or does it have something to do with the cat. converter?
 
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Ive run multiple 5W30 and 10W30 synthetic oils, high mileage and regular syn, with no troubles in this truck, I figured with 120k miles it couldnt hurt. I'm the only one who maintains it and the only one who has since 40k miles. I do need to get around to changing the plugs and wires soon. I was thinking a good idea would be to scrub the tailpipe where it is sooty and get it real clean, and monitor the oil consumption and the tailpipe color over this current oci with the Supertech 5W30, I'll look and see if it gets real sooty again, and I'll be sure to cut open the Baldwin filter when I change the oil around 5500-6k miles
 
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Originally Posted By: old1
Not really pertinent to the OP's question, but along the same lines something I have wondered about. I know that manny manny years ago, if looking at a used car, you would look at the tailpipe, and if it was white, you could be pretty sure it wasn't an oil burner, and if black, either it burned oil, or it was burning excess gas, which could be cold weather short trips with the choke on most of the time. But NOW, it seems all the cars, always have black tailpipes, even though they burn much less gas and oil than back then. WHY? Is it the gas of today, or does it have something to do with the cat. converter?


Back in the days of leaded fuel, it was common for well-tuned cars to have a white or grey tailpipe after a good highway run. When leaded gas disappeared, I stopped seeing that even on well-tuned non-catalyst cars running unleaded gas (including my own). They didn't turn black running unleaded, but they were a natural metal color (no deposits to speak of). Many cars today seem to have sooty pipes - even brand new ones. Perhaps spark plug condition is a better indication of an engine's state of tune with today's cars and fuels (?)

Andrew S.
 
The duel tail pipes on my 2014 Mustang GT are perfectly clean with no soot buildup. The single tail pipe on my 98 K3500 with the 454 also is not sooty at all. My 98 K1500 with the 5.7 which I've owned since new, has a Borla Cat-back exhaust system on it and both pipes are very sooty.
 
I think some vehicles just go pig-rich on WOT.

Also, I recall reading that DI gasser can have some large particulate matter (PM). Usually gas exhaust has small PM sizes, while diesel would have large diameter "soot". Kinda makes sense, as the line between gas and diesel got a bit more fuzzy with direct injection gas; less time for atomization. Anyhow, with higher specific output and the press for light weight, IMO just a guess some of the newer cars with sooty rears is from the combination of the two: running rich to prevent engine damage (pinging, piston melting) and/or increased soot output due to DI.

Why a 4.8L Vortec would have that issue though is beyond me--way too many of those didn't have any issue of the sort to guess as to why. Have to guess it's just slightly excessive fuel or oil usage plus many miles to build up a layer. If gas&oil consumption isn't excessive, I'd ignore it. All exhaust has soot in it, maybe he got lucky and has the one vehicle which wants to deposit it.
 
I just walked out to my 2012 Chevy 4.3 truck and the tailpipe looks a little sooty w/black soot. I stuck my finger in it and pulled out a very little bit of black residue on my finger. My Chevy Cruze had some gray residue inside the tailpipe, but only a very small amount.
 
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