I replaced the pigtails to the valve cover gaskets recently. I soldered the wires on and then put heat shrink around them and then wrapped them with electrical tape, 4 glow plugs in one and the 4 injector wires in the other. I made it about 200 miles before the heat got to everything and melted everything together and I had "issues".

My question is: Do they have a high temp heat shrink material that will handle the conditions under the hood and if so what is it and where can I find it? I'm also open to other types of ways to seal everything up if anyone has them.

 

I "think" (we all know how that works), rather than a combining the wires in a single tight bundle they should be loose with the ends exposed (last 1" maybe).

The GP Circuit draws a tremendous amount of amperage to bring the GP's to an adequate temperature. And, amperage generates heat. With no where to disperse it, insulations become hot, melts, becomes brittle, etc..

Any UVCH that you see with any appreciable miles shows signs of this. Especially with loosened connection.

Just a suggestion.

 

You might have a look at this [LINK].

Using the wrong crimp material (like the aluminum butt splices) for something high-amp like a glow plug can easily fail.