Unknown substance on exhaust (possibly tar)

[Evo13]

Performed an oil change for my M3 this weekend and while I was underneath, I visually inspected the bottom of the car. I noticed after the primary cats, on the one side of the exhaust pipes closer to the driver side, some substance caked on it.

My only assumption is that it could be tar, but I have no idea. Even if it is, how would I get that off? It was not flaking off or brittle. Any suggestions or ideas?

[roastbeef]

its probably a plastic bag that blew under the car while you were sitting at a light and shrunk up to the exhaust when it got close. ugly, but not a big deal. just leave it alone, it looks like its done cooking.

[Evo13]

Originally Posted by roastbeef

its probably a plastic bag that blew under the car while you were sitting at a light and shrunk up to the exhaust when it got close. ugly, but not a big deal. just leave it alone, it looks like its done cooking.

I guess that could explain a slight burning smell I notice when I drive. I got the car detailed not to long ago and the engine was detailed as well, I figured it could be whatever product "burning" off the hot engine and producing that smell, but I think you are right.

[roastbeef]

yea, it happened to my wife's lexus some years ago. i got it off the best i could pretty quick, but it sort of wants to cling to it like shrink wrap when it gets hot enough. doesn't look like there is much you can do at this point.

[pbonsalb]

Solvent or wire wheel on a drill to remove?

[Scharbag]

Or go for an Italian tune-up. Get the pipes really hot and it will be gone soon.

[deansbimmer]

Plastic bag melted to the pipes. Wire cup brush on a drill will remove it the fastest.

[MPowerZ32]

+1 plastic bag. Razor blade scraper also works.