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Born to Lose, Live to Win
 
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black powdery substance on rear of car

i have been noticing, usually after washing and waxing, that after a drive i have a very fine layer of black powder covering both rear fenders. looks like black dust. i thought it could be exhaust or the tires were rubbing.

the tires are not rubbing and are brand new. there is no sign that they are rubbing. the car is white so i see this easily and its always there after i drive it.

im concerned because i ive never noticed any of my other cars with any such black dust. perhaps its just road dirt. does anyone else have this situation. the car has no cat, and it doesnt smoke, drip oil, or even burn much oil at all.

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Things fall apart; the center cannot hold…

1983 911sc
2025 Chevy Colorado ZR2
Old 07-27-2007, 05:12 AM
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JBO JBO is offline
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Yea, it's your tires being vaporized....I have the same thing (only on the rear), and I guess that is why the soft Dunlops only lasted 4,500 miles. The BFG's are doing a little better, but it looks like they will be gone at 5k. That will be my third set of rear tires and fronts still look fine! I'm thinking of going with a V rated tire next time that will hopefully last longer on the back.
Old 07-27-2007, 05:23 AM
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Normal for our cars...it's a combination of dirt, rubber, brake and combustion debris.
Old 07-27-2007, 05:23 AM
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thanks alot.
JBO, your getting 5K miles on those rear tires?
ive got about 3.5K on my tires and they look brand new....despite that they are being vaporized. I bought Fuzion's. Ive seen some negative comments about these tires by some people, but I gotta say I am very impressed and they are very cheap and I think I will get 15K out of them at least
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Things fall apart; the center cannot hold…

1983 911sc
2025 Chevy Colorado ZR2

Last edited by ramonesfreak; 07-27-2007 at 05:33 AM..
Old 07-27-2007, 05:30 AM
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I would that some of it is burned oil. The black dust increases with the amount of oil leaks.
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Old 07-27-2007, 05:33 AM
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No it's not burned oil in my opinion.......which would have a degree of oily-ness to it.

It has a powdery consistency like brake dust...which is what it can be altogether. If you carefully wipe your car with this stuff under a soft cotton cloth, it actually seems to act as a clay bar on your paint !!

- Wil
Old 07-27-2007, 10:04 AM
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might want to closely inspect your fan and a/c belts.
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Old 07-27-2007, 10:04 AM
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brake dust sounds accurate. brand new fan belt. removed AC belt long ago. definately not oil. looks more like soot (sp?)...i.e. Ash but powdered ash.
thanks
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Things fall apart; the center cannot hold…

1983 911sc
2025 Chevy Colorado ZR2
Old 07-27-2007, 10:08 AM
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Very common. Keep a good coat of polish on the car and a light rinse takes care of it. I usually have to rinse her off at least once a weekend after driving.
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Old 07-27-2007, 10:13 AM
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whoa, street tires that last only 4.5k miles??? What kind of tires are you using? My S-03s lasted more than 5 times that long. Are you using excessive toe?

I had to go with V rated tires on the back of mine since the Z rated S-03s are NLA. I'm still slippin and sliding back there after about 300 miles, although it's settling down a bit now. Next time I'm going with a full set of Z rated tires no matter what, even if I have to buy Pirellis. I think these Bridgestone V rated tires will last over 20k miles easily, maybe even 30k miles.
Old 07-27-2007, 11:20 AM
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I have the same thing. It's brake dust. Porsche OEM brake pads are notoriously dusty like this, so on a white car you'll definitely notice it. I switched to ceramic pads and I don't notice it nearly as much.
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Old 07-27-2007, 11:23 AM
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My '89 silver 3.2 gets covered. It mostly brake dust.

David
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Old 07-27-2007, 12:00 PM
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I run non-OEM pads ( Pagid Orange) and find the same dust either way.....

- Wil
Old 07-28-2007, 11:51 AM
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Quote:
Originally Posted by JBO View Post
I guess that is why the soft Dunlops only lasted 4,500 miles. The BFG's are doing a little better, but it looks like they will be gone at 5k.
Do you have a Limited Slip rear end?

I only got 12K out of the rears

Old 07-28-2007, 12:49 PM
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