I had a new left front fender put on...nice job. 1989 300te. Is there any rustproofing I should do, over and beyond what they "said" they did in the shop? What are the "rust areas"
of the 300te? I would like to keep this car "forever". It is salt time here in the Northeast.

What did they do in the shop? Mercedes injected an anti-corrosive wax in crevices that were not easily coated with paints.

In my 1992 300D manual,

MB is against aftermarket rustproof or undercoat.

They say that factory wax based rustproof will last car's lifetime. Aftermarket rustproof can destroy original rustproof.



Your vehicle has been treated at the factory with a wax-base rustproofing in the body cavities which will last for the lifetime of the vehicle. Postproduction treatment is neither necessary nor recommended by Mercedes-Benz because of the possibility of incompatibility between materials used in the production process and other applied later.
1992 Mercedes 300D owner's manual, page 93