I bought a used uncollected header the other day and after looking at it I noticed the O2 bung is located just about 4 inches away from the engine side face. I would have thought it should be welded in farther down the runner to avoid the heat. Is this header going to melt my sensor?

Thanks

 

If your sensor is for the stock sensor (Narrowband) it will be fine. If it is for an aftermarket wideband sensor it needs to be much furth down the pipe.

James

 

if you look at the factory position , you will see that it is only about 4-5 away from the engine. you should be fine. People who run wideband sensors move them downstream a bit further to increase life span