A mechanic told me that headers turn blue in color when the car is running rich?? Is this true?? (I am running a straight pipe)My headers have a blue color but kinda rainbowed like in an oil puddle. But most other cars I have seen with headers have this same color to them. So what does it mean?? Is that just how they wear?? just curious thanks

 

If they have a metallic rainbow color, I'm pretty sure it's because you have stainless steel headers. they discolor once used.

 

Its called heat.

 

Thats from them getting really hot, youre probably not running rich