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Discussion Starter · #1 ·
Hello,
I debated a while before asking this question. Since I am a fairly new owner with a previous rental vehicle, I wanted to wait awhile before asking.

I live in California, and thus have a lot of environmental additives in our fuel. We just made the switch from winter to summer blend. In the few tanks of gas I've burned so far in this car, the exhaust pipes have a definite layer of black soot inside the pipe. As a matter of fact, I noticed it because of the water that flows out of the pipes when the engine is cold.

This water from the catalytic converters mixes with the soot already present, and leaves a trail of soot I have to clean every time I wash of the car. I sometimes stick my finger in the pipes after driving, and I always find a fine layer of soot. I wipe it out with a rag and it always comes back.

I traded in an 11 year old Ford Explorer with the 5.0L V8 engine. After 11 years of driving in this State, the tailpipe was always ash white. We are talking about a 155,000 mile vehicle on the same 02 sensors and catalytic converters. I always ran regular grade unleaded.

Does anyone else have the sooty exhaust? I would be interested in hearing from owners in other states that have what I consider cleaner fuel than here.

Lastly, my other car is a Lexus V8, and it too has sooty exhaust. It is a variable-valve timing 32 valve engine. I always use premium in the Lexus because it is required, but strictly regular grade 87 octane in the Enclave.

With only 12,000 miles on the car, I shouldn't have pcv problems or leaking valve stem seals. I am monitoring my oil usage during this first month of ownership.

Perhaps it is the design. Who knows? I still get the mileage I am supposed to, and the engine is very peppy. I'll check the mileage and tailpipe condition when I go to Atlanta next month. I expect better mileage once I get different gas in the other states. That has always been true whenever I drove out of state in the past.

Just asking.

Thanks
 

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I don't there is a problem.
I have the same situation, and as you have discovered, simply washing and drying the exhaust tips keeps them shiny.
Now that spring is here, I am going to try some chrome polish to see if that helps.
You have probably noticed that the tips are not part of the exhaust pipe, but a "collar" surrounding it. The air flow between the pipe & tip keeps it cool, so the hot exhaust gases never directly contact the tip.
This may explain the darker discoloration.
 

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I have the same issue and run Hess or Shell gas in my 'Clave. I have been keeping an eye on it the last few weeks to see if the changing fuel blend makes a difference. For about a week after we bought the vehicle we noticed a strong "chemical" odor coming from the exhaust while the vehicle idled. I assumed it was just a coating on the pipes "burning off".
 

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Discussion Starter · #5 ·
I assume I am using top tier fuels. I use Chevron exclusively in the Enclave. I sometimes I use Union 76 in my Lexus, but never off the wall brands.

The exhaust pipes are beautiful. I try to keep them clean and shiny, hence this topic. every morning after warmup the black trail is there. By the time I get to work the soot is inside the pipe.

I had 2 people stop me yesterday and wanted to talk about the car.
 

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Discussion Starter · #7 ·
Possibly so. I was just checking to make sure I don't have a cause for worry.

It seems to be a thing with multi-valve engines. As I stated before, my Lexus GS with multi valve engine does the same thing using premium fuel.

I just checked my engine oil and I am about 1/2 to 3/4 qt overfilled. I called the dealership and they want me to bring it back. Extra oil in the crankcase is not good, as the extra oil gets into the intake and out the catalytic converters.

I have oil in my air intake going into the throttle body and intake. the engine is supposed to take 5.5 quarts of engine oil. The dealership service department said that extra oil won't hurt, but I beg to differ. The owners manual cautions against overfilling.

I am going to have it checked. I'll keep in touch.
 

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mine goes in the shop tomorrow I will ask them if there is any significance with the sooty pipes....Ill let you know tomorrow!
 

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I also have that bottom lip soot. Bugs me. I thought it was due to a rich idle mixture, but accumulation after a long trip proved that was not the case. Since the chrome tail tip lip sits inside the tailpipe, possibly the differential in temperatures is the cause for the accumulation. On a similar point, it doesn't take long for the back window to get dirty even without rain. The tailgate section is always the dirtiest part on the car. Must be related to the aerodyanamics
 

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I asked about this same issue shortly after we brought our home. It is quite annoying, but apparently normal. I have noticed that same "soot" on the chrome tailpipes of brand new Acura MDXs and other high end newer models. It would seem to me that this is indicative of an overly rich air/fuel mixture, but apparently it is normal for the modern high performance engines.
 

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Every vehicle I've owned for the past 15 years has had the black soot inside the exhaust; it's normal. We currently own, in addition to the Enclave, a 2002 Avalanche, a 2002 Taurus, and a 2007 Civic. They all exhibit the sooty exhaust. We owned a 2000 Explorer with the 4.0 OHC V6 and it also had the black soot.

I think you don't notice it on a lot of vehicles because they don't have a shiny chrome/stainless tip and the tailpipe turns down at the end. It's more easily noticed with the short Enclave exhaust tips coming straight out the back. The mufflers being right out at the end of the exhaust instead of up under the vehicle might also contribute to the issue.
 

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talked to my service manager today, it is normal....he said if it was running too rich there would be an indicator light on....ie check engine, etc
 

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I usually get this after a rich Chinese meal....
 

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Discussion Starter · #14 ·
I just traded a 1997 Ford Explorer XLT 5.0L V8 that always had a ashy exhaust. It has never had a sooty exhaust. I have owned numerous Fords including the Mustang and Thunderbird Super coupes, and they didn't have soot either. Now the multi-valve engines in the "SHO" did have sooty exhaust pipes. I verify by running my finger inside the pipe and checking.

I think it has a lot to do with the multi-valve arrangement and the fuel-air mixture required to run this type of engine.

Right now I have too much engine oil in thecrankcase of my Enclave, and this will be fixed tomorrow. If I see soot after that I won't worry about it since everyone else seems to have it. Just the nature of the beast.

I'm happy.
 

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Mary had a little lamb,
It's fleece was black as soot.
And everywhere that Mary went,
His sooty foot he put.
 

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GSEREP1 said:
I just traded a 1997 Ford Explorer XLT 5.0L V8 that always had a ashy exhaust. It has never had a sooty exhaust. I have owned numerous Fords including the Mustang and Thunderbird Super coupes, and they didn't have soot either. Now the multi-valve engines in the "SHO" did have sooty exhaust pipes. I verify by running my finger inside the pipe and checking.

I think it has a lot to do with the multi-valve arrangement and the fuel-air mixture required to run this type of engine.

Right now I have too much engine oil in the crankcase of my Enclave, and this will be fixed tomorrow. If I see soot after that I won't worry about it since everyone else seems to have it. Just the nature of the beast.

I'm happy.

As speculated: air flow (dirty hatch gate!) VVT engine, soot...............normal!

CAUTION! Chrome tips are very hot for several minutes, and can burn badly after a drive!! Keep little ones away from the rear, and clean well after a few minutes only!!
 

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Discussion Starter · #17 ·
They sure are! I found that out the first time I did that after a long drive. Burned my index finger real good. Now I wait awhile before checking.

Since I don't have to worry about it anymore, there is no need to do it again.
 

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I live in Kansas city and have the same "problem" on mine. I put a little charcoal lighter fluid on a rag and it seemed to remove some of it. I didnt work very hard at it as i was in a hurry, but with a little elbow grease, it may all come off. My 06 avalon did the same thing.
 

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I have almost 10,000 Miles on My Clave and do not have the soot problem. I just have a little light charcoal tint in the inside
of the Exhaust but none on the Chrome Tail Pipes out side.
 

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bsox said:
I usually get this after a rich Chinese meal....
LOL - I was going to make a similar comment but couldn't bring myself to do it!
 
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