: carbon on tailpipes, and why?



scottm1313
07-26-07, 04:29 PM
Can anyone give any suggestions to why I now have lots of carbon deposits on tailpipes of my 97 etc. I recently switched to castrol high mileage oil, and have used it for 2 oil changes, each change is done at the 1500 mile limit that that motor has had its whole 106k miles. I had never noticed it when using conventional castrol / penzoil 10/30 oil, just wondering if the "conditioners" in the high mileage oil are somehow moving the carbon around and out the tailpipes. The engine purrs like day one still with 106k on it, and has been "over" maintained its whole life. any thoughts from anyone here would be most appreciated, I'm a fan of w.o.t's and do them often to move the crap out, but this carbon seems odd, as it's never spit any before out the pipes. thanks Scott

AJxtcman
07-26-07, 08:25 PM
First the earth was hot, Then it cooled, Then the Dino's came and went, Now we burn dead Dino's, The Dino juice is mixed with chemicals to clean the back of the valves, This can cause large amount of carbon to develop when burnt. Solution don't burn a gas with high level of additive compounds

Submariner409
07-26-07, 08:51 PM
:confused: If your new oil with "conditioners" was moving carbon around to blow out the exhaust, you would be burning a LOT of oil to get the "conditioners" to the combustion chamber. I seriously doubt whether or not you need a high mileage brew.....100,000+ is not a lot of miles on the basic engine components nowadays....taken to extreme, that's only 9 oil/filter changes on a late V-8. 1,500 mile oil/filter changes are a waste of money and time unless the car sits for weeks and then goes 3 miles a trip. You've put more wear on the engine doing dry filter starts than the 106,000. Most gasoline is pretty good, unless you fill up at a station that sells 50 gallons a month. What has changed???? Gas mileage??? Driving habits??? Oil consumption???
Something has changed recently to cause some black fluff in the tailpipe(s). Do a search for stuff like gasoline additives, TECHRON, etc., and try to figure out why AJxtcman and I posted a litany of "good gasoline" info 3 weeks ago, and AJ actually posted some GM recommended gas info......... As we used to say in diesel boats "If you can't keep your s**t in one sock, pack up and ship out....". (but I don't have an opinion...)

AJxtcman
07-27-07, 05:49 AM
Dino juice is dirty.

scottm1313
07-27-07, 07:06 AM
Hey submariner, thanks for the reply. Here in Maine, northern to be exact, we don't have much choice on gas brands, mobil and irving are the only ones here. That said, nothing really has changed with driving habits, other than the car being used more on the interstate on a daily basis, with about 60 miles driven a day. Gas mileage actually is better, with it being in the high 28.9 range at 60mph daily. Oil consumption is the usual 1 quart per thousand miles. The engine runs like day one, actually i am amazed at how perfect the car runs, pulgs and wires, coil were changed at 90k, and coolant is changed every year. The car has been over maintained like i said, and i love the car. The ETC will soon become my toy and be driven less, with the recent purchase of a new DTS. That said, is there any issues i should be aware of with driving the ETC less, and letting it sit for longer periods of time? You guys are great with your comments and input, and are most appreciated. Scott

blunted
07-27-07, 03:51 PM
I have pretty big pipes on the Eldorado and notice I'll get a little carbon on them . There's alot of stop & go here and I strictly use Shell 93 with 10-30 Castrol high mileage (96K on her).. I think its normal to have some on there, if its getting really caked up then you might have some other issue. I'm not sure if the Castrol has anything to do with it but when I open my oil fill cap it looks amazingly clean in there so I'll stick with it.. also it doesn't have the "starburst" symbol which I think means it has more ZDP in it.

Submariner409
07-27-07, 08:24 PM
:stirpot: AJ........Have you just dumped a bunch of $$$$ into an ethanol still ???
scottm........keep an eye on your oil consumption. A few N*'s eat a quart or so every 1,000 on the highway, most get 1,500-2500/qt., and a few get over 3,000. The next time you change your oil/filter, prefill the filter and then fill the pan until halfway up the dipstick hashmark. Take a short drive. Back in the garage pop a brew and let the engine sit for 5 minutes. If necessary, add only enough oil to get back to the halfway mark. That should be 7 1/2 quarts. .......and.......when you rub your finger in the tailpipe (woohoo!), is the black stuff dry dust or oily soot? Dust is a rich low speed mixture. Oily is.....oil. Some engines will blow/burn out the first half-quart of oil if you fill them to the "F". (If you're driving 60 miles/day, then you're changing oil and filter about every 5 weeks. Overkill.)

AJxtcman
07-27-07, 08:52 PM
:stirpot: AJ........Have you just dumped a bunch of $$$$ into an ethanol still ???
when you rub your finger in the tailpipe (woohoo!), is the black stuff dry dust or oily soot? Dust is a rich low speed mixture. Oily is.....oil.

You should have posted this first.
100% of all cars have carbon in the exhaust system.
The Catalytic Converter will do what to the Rich mixture and then convert it into what?
We are talking about Dino Juice. Not an antique car.
.
.
BTW My Dino is an official IT.

Submariner409
07-28-07, 07:21 PM
A properly operating catalytic convertor does just what its name implies : it uses heat, air, palladium, rhodium, and platinum to convert unburned hydrocarbons into water and carbon dioxide, not carbon.

scottm1313
07-29-07, 01:53 PM
Hey submariner409, sorry, the rub on the tailpipe presents a dry soot, never oily or wet. Scott

AJxtcman
07-29-07, 02:08 PM
Hey submariner409, sorry, the rub on the tailpipe presents a dry soot, never oily or wet. Scott

That was my point.
I hate to touch the inside of the pipe. Very messy
I had an exhaust system off a CTS and I was installing it on Friday. I had it leaning on the wall backward. I had to swap ends before going under the car. some how I touched my leg on the pipe and I had grabbed the inside when I pulled it off the wall. I had so much soot and it is like anti seize hard to wipe off and it gets on everything.
Every Exhaust has soot.