If you insulate the line for the purpose of protecting it that may cause the line to hold heat and cause failure. You could fabricate a sheet metal heat shield and hose clamp it to the exhaust pipe at that point or you could use a stainless braided air compressor hose in that section above the pipe, it is made to take the heat or a hard line in that section would work too. Leaving the line unsheathed will aid in keeping it cool. The heat shield on the exhaust pipe would really help dissipate heat when truck is not moving.

You may have no trouble with it at all with a free flowing exhaust. It's the ones that are all choked down with allot of back pressure that build so much heat in the pipes then radiating it everywhere.

Originally Posted by bender

If you insulate the line for the purpose of protecting it that may cause the line to hold heat and cause failure. You could fabricate a sheet metal heat shield and hose clamp it to the exhaust pipe at that point or you could use a stainless braided air compressor hose in that section above the pipe, it is made to take the heat or a hard line in that section would work too. Leaving the line unsheathed will aid in keeping it cool. The heat shield on the exhaust pipe would really help dissipate heat when truck is not moving.

Bender is right on, in the old days we used DOT copper tubing for the air lines as well as wire brade hose. The trailer dealerships for the most part still stock the DOT copper line, and "no", you don't want to consider standard water line copper tubing, it is more brittle and has a thinner wall thickness, it will not stand the vibration. You will still be able to use the same DOT brass fittings with the copper tubing, just remove the shiny stainlees steel insert that goes up inside the nylon line to keep it from collapsing, it won't work with the copper, and the copper won't cpllapse as bad as the nylon, just take a pair of plyers and grasp the stainless insert, and it will com right out of the fitting. Just use the copper in the area near the exhaust line, use nylon everywhere else.

Originally Posted by Hanadarko

Good information...
What I did for now, is use split-loom plastic standard wire loom and tied it off away the best I could.
I am going to watch it and see if the plastic loom starts to melt in any way.

I used hot water heater split foam insulation on the AC lines that run even closer to the exhaust pipe and the foam isnt even melted.
That stuff melts if you look at it the wrong way!

They make high temp split loom fwiw. Personally I would take some half inch airline split it down the length, and zip tie it in plac over the 1/4 in stuff. You could also do a heat shield preferably attached to the heat source with an air gap. Or wrap with turbo tape.