jobear

2001 Cpe with 62K miles. Bought last October. Car in immaculate condition. I am now getting black spots show up on the rear end after a drive. A lot of black spots. Probably soot of some kind. It never used to do this. I have put a new Corsa exhaust system a while back. I some some spots on the garage floor and some black on the chrome tips as well. Not a lot. I keep them spotless but I can see black that has dried like a water base. It cleans right off.
I always idle to or near operating speeds before driving and do not make short trips to the corner store. It is a garage queen with only 2400 miles since october.
The black spots do dust right off but have become more aggressive.
Probably took a 60 mile drive today with a couple of stops, and this is what I have.
I posted this on the regular forum chat and nobdy thought it was anything to worry about but it is worse all the time it seems, and I am concerned.
Any ideas? --- thanks in advance.

[IMG][/IMG]lately.

EStreeter

The first time I used a top end cleaner in my engine and took it out for drive to blow out the crud my rear end looked like that or worse. It was covered with soot and other stuff that probably blew out of the cylinders after becoming loosened by the cleaner. I have Spiral Gray Metallic paint so its not so noticeable but there is usually some spots like that on the back whenever I wash it.

Those spots could be from exhaust emmissions or maybe something on the roads you drive. The rear end must create a small vacumm that sucks up stuff. Mine gets real dusty if there is anything loose on the roads.

huttler

Do you have a cam? My car does the same thing, it started after my cam install. I think it's soot blowing out of the exhaust. If you don't have any engine mods, your engine might not be running properly due to a bad sensor, etc.

bobby777

Nothing to worry-all cars blow $hit out the exhaust--If it was wet than that would be signs of blowby

~Josh

After using a claybar I applied several coats of Zymol wax (carnuba)

As mentioned, a good top end cleaner (like Seafoam) will help out after a few treatments. I did all of this plus added an oil catch can, with great results.

jobear

Like I mentioned it dusts right off. But I am concerned that it is increasing.

jobear

No engine mods at all. How do I check for a bad sensor? Mechanic?
thanks

huttler

It was just a guess, if you haven't noticed anything wrong such as decreased gas mileage, I wouldn't take it in.

madmatt9471

It almost looks like excessive condensation being held in the mufflers!

It might come out during the initial begining of your drive and then collect soot and stick to the back end!

If you are seeing this after a drive, then what I'd do is during the middle of the drive pull over and clean the backend and continue and on the next stop see if it has built back up - if it has then you will have a deeper problem, which'll be for another discussion

Give this a shot!

Thanks,Matt

BLOWNBLUEZ06

If you blew part of your cats out or even part of them, it would do this. Cats trap soot and there is a strong vacuum behind the car when driving that will throw any particles leaving the exhaust on to the rear bumper. I have no cats and I always have a considerable amount of soot on my rear after a drive. That's the cost of performance.

~Josh

I brought up the top end cleaner and catch can for a reason. Your '01 has the much lamented piston rings that supposedly aren't the best for oil control. You mentioned the problem getting worse right? Perhaps it's a carbon issue like my '01 had.

After a few Seafoam treatments the problem is nearly non-existant (black specks)

bubs99

http://i150.photobucket.com/albums/s...f7b4cf4f1e.jpg

jobear

???

jobear

Good idea - I'll try that. I just went out and checked and although they seem for the most part to dust right off I do see a bit of a residue when I use a finger to test how easy they wipe off. Also just for info I always use Chevron super.

jobear

I think my mileage may be down a bit.