Need to insulate a small harness from headers

[SSLance]

I've got a small harness with wires that run to the temp sensor, knock sensor, and oil pressure sender in it that runs very close to my driver side header near the oil filter. I can't seem to come up with a way to secure it to the block to hold it in place but in most cases it stays away from the header and does okay.

Over the past year the plastic sheathing it is in has melted away in a section about 2" long where it is closest to the header, but the wires themselves did not get damaged.

I'm trying to come up with a solution to wrap around the harness to protect the wires from the heat but am coming up empty. There really isn't any other way to route it as everything it connects to is also under the header. I can put new sheathing over it again and hope for the best maybe even adding a layer or two of electrical tape, but would like to try something a bit more permanent.

Any suggestions?

Something like the metal tube on the passenger side for the wires coming off of the starter would be great, but there is nothing to attach it to to hold it in place that I can see.

What I'd like is some sort of insulating tape that I could wrap the harness up in...is there such a thing?