Obviously a EPA 07 engine. I think the biggest problem is that people don't polish the tip. I use the same as I use on the wheels. The tip still shines except for a spot on a corner edge. It is not chrome but porcelain I believe. I would call Freightliner and ask about a replacement or what can be done for it. 1-800-FTL-HELP (1-800-385-4357) or
Freightliner.