Protecting wiring harness(es) especially in engine bay to ensure longevity (1 Viewer)

[sunrk]

In our older 80's (esp. the pre-8/92 ones) the wiring is getting very aged and especially in the engine bay area is subjected to a lot of heat plus any wiring to/from or near the engine gets a lot of vibration.

Does anyone do anything special to protect or just otherwise ensure the longevity of the wiring harness(es) in the engine bay given none of it is now available as new oldstock if wholesale replacement of any particular section is needed?

One of the hardest areas to do much about seems to be near the starter motor area in my 80 where there's a big plug/socket wiring harness connection which is basically fully exposed to heat and vibration without any really simple way to give it a lot of protection.

Craig.

 

[shocktower]

My friend uses a harness wrap it seems to do good

 

[Qball]

With the amount of heat in the engine bay and 25+ years the only insurance you can have would be a new harness while they are still around.

 

[TheLCProject]

I'm dealing with symptoms of this issue on my 1995. I had severe heat damage on my neutral safety switch circuit.

At least three of the nine wires were damaged and didn't have continuity and the others probably had some damage too. I think the primary culprit is heat on the horizontal portion of the main engine harness right below the intake runners and above the starter. It's right where everything branches off. At that spot, there's a melted out divot and it basically caused the wiring to the neutral safety switch to burn up and corrode away, all the way to the switch itself.

I also think part of the issue is that the original wire loom retainers are super brittle and most have broken and this causes the wiring to rest where it shouldn't.

I'm currently rerouting a new set of nine wires and will be wrapping the damaged portion on the portion by the EGR with heat wrap.

I also bought a harness out of a wrecked 95 to begin a full rewrap to have a spare ready in the event I get another electrical issue.

 

[Rifleman]

The wiring harness used on our trucks is great compared to some I've had to work on, you haven't lived until you've had the pleasure of working on the wiring harness of a 90's era Mercedes Benz.

The insulation that the Mercedes Benz vendor used was defective. With age, and exposure to heat it became so brittle, that it falls off of the copper wires from vibration, or if you just happen to touch it, leading to all kinds of electrical shorts.

A replacement harness, if you could even find an NOS one, will cost you thousands of dollars!

 

[Michael Hanson]

Hi, The wiring harness clips are failing on our 80 also. I'm using wide ac wire ties to replace Oem clips. Mike