Ive got a stupid question, but no one has been able to answer why other than that some do this and some dont, so i thought id ask the board. My 2005 supercabs exhaust manifolds and muffler look like they are 20 years old already with alot of rust. The rest of the exhaust which i know is stainless steel doesnt. ive looked at some other 04 and 05 trucks and some look like this but most dont.
Just wondering if anyone has a theory on this and if its anything to be alarmed about

 

The manifolds are cast iron, and will get rusty, but it will take 70 years for those suckers to get any rust that is harmful, so dont worry about it.

Your muffler should be stainless too. Ford uses a low grade stainless in the exhaust, that will turn brown but should never actually rust.

 

Thanks for the info Bob Jusnes. I seen your website and figured you know what your talking about. I tend to be a worry wart at times.

 

No problem, you wont learn unless you ask questions! I learned all i know by worrying and wondering!!