That's the temperature at which pure aluminum actually turns into a liquid. Aluminum is quite ductile and will begin to deform well before its melting point. Just checked on McMaster Carr, and aluminum tubing is generally rated for up to 300°F. I would imagine this rating is lower or at least not for long periods of time. Furthermore, this rating could be even lower if Snabb (and I'm not trying to bad mouth them, they seem to be a great company, I have their TCV) or the company they buy tubing from did not pay the extra money for certified material. This sort of stuff is actually guaranteed to have specific properties and comes with a piece of paper showing the material testing results, etc. However that certification costs a lot of extra money so most people don't go for that option which is okay, you just over-engineer and design for the operating parameters.Aluminum melts at1,221°F..so you are really dillusional thinking you have anywhere near those temps anywhere in a vehicle.. G et a grip..