After killing my second wideband sensor I bit the bullet and picked up a heatsink for it. I used to have a homemade copper heatsink when I had the Megan tubular o2 housing but it didn't fit right on the evo 3 o2 so I took a chance and ran without it, of course I paid the price.



This is directional and has to be installed in a certain orientation so the flow enters it properly. They include one copper washer with it but it was not tight in the correct direction so luckily I had a few other crush washers on hand, I think I added 2 and then it tightened in the proper orientation.