Adam - Brass fittings are what are normally available, and brass is what I have in my car. Just remember to use thread sealant when installing the fitting into the thermostat housing. There is no challenge between the aluminum engine parts and the brass, especially if you use any brand of good antifreeze. If you are actually looking at copper fittings, I think that they would be very soft, and easily damaged during installation. I can't recall ever seeing copper threaded fittings, to be honest with you. We have very inexpensive kits prepared with all the parts, if you choose to go with a package rather than piecing it together yourself. Contact me, or Darryl Tinnerstet at www.delorean-parts.com . I know that most of the vendors also have similar kits. It is an excellent system for eliminating air pockets in the engine. I have installed this concept in my other (non-DeLorean) cars as well. Toby Peterson VIN 2248 Winged1 --- In dmcnews@xxxx, "Adam Price" <acprice1@xxxx> wrote: > > I am trying to make my own overheat protector and I was just wondering if copper is okay to use? All I can find are copper fittings, so will the copper react with the aluminum or the antifreeze in a harmful way? What type of fittings are sold with the overheat protector kits? >