Kind of crack in chassis at rear bumper post
 

To work on the exhaust, I have removed the rear bumper cover and bumper. Yesterday I noticed a sort of crack in the glue kind of stuff on the chassis, see picture below. On the left side of the car (where this picture is taken) it runs quite a way forward. Also around the rear part. On the right side It is only visible around the bumper post, not running forward along the main chassis beam.

I have taken quite a bit of the car apart over the last year, with a lot of carpeting, panels, heat shields and liners removed and I have not seen this in other places.

A few questions on this;
1. What is this glue kind of stuff called?
2. What would be the cause of these cracks?
3. Are they structural or only cosmetic?
4. Any advice on a fix?

Attachment 23745

Hello Marc, is the white round part on the right part of the picture, the bumper strut?
If so, the glued section (cracked), perhaps was caused by a light impact on the bumper causing the dried glue to crack..? :rolleyes:

Yes, that is the bumper strut indeed. The car has taken a hit sometime in its life and this is most noticeable in the right rear. The longest crack happens to be on the left...

Any advice on this?

IMHO, I would only fill the crack with new sealant, to keep moisture and water away, I seriously doubt that the frame/body is damaged by the impact, but to be sure you may want to meassure it to see if you find any discrepancies.