Idea for brittle plastic wiring harness

I've seen other threads on this elsewhere, but figured I'd throw my solution out there as well.

I was prepping to service the valve cover gaskets, semilunars, PCV, and washer seals and found that the plastic wiring harness sitting above the valve covers had broken into a hundred pieces. Rather than risk dropping plastic into the valve covers as I removed them, I decided to completely remove the brittle plastic and replace with a heat and abrasion resistant loom material from O'Reilly's. Allegedly good to 500F and will protect the wiring from abrasion at contact points with the valve covers. The cool thing is that the material is flexible and should make valve cover removal much easier.

 

I'm actually doing the same thing on a '56 I'm working on. We also use that type of material in scuba as a protective layer over our air hoses. It's basically like a chinese finger trap.

 

I would think that the adhesive on the tape that's used would melt during the first hour of driving. It would then gather dust, unravel, and cause a mess. If I were doing that fix (and it's a good fix too!), I would put a good cable tie around the ends of each of the tapes to keep them from coming undone.

(And I would use the black cable ties rather than the white ones which harden and break a lot sooner than the black ones, but that's just my personal experience).

 

I'd go with some COT around it:

https://tinyurl.com/y8tz57rv

 

This is actually one of my concerns of doing this job! What I learned while doing this was that there was a ton of electrical tape and some exposed wiring sitting under the plastic that made it 25 years without melting. I also learned that the upper temperature boundary for electrical tape is usually about 200C, which should be able to handle even a vastly overheated engine. Using these two facts, I reckoned that it would be ok to secure the loom with electrical tape, but now I'm back to second guessing. I'm going to do the valve covers in a few weeks and will report back on it.

 

This was my solution and works great,
Tesa tape
https://www.tacomaworld.com/threads...-4-v6-damaged-wiring-harness-solution.576633/

 

On reconsidering the specs, it seems like the vinyl and adhesive have different melting points and it's probably better to go with a higher tolerance for heat. Thanks for the recommend on tesa tape.

 

Perfect

 

I also did the Tesa tape after seeing it used as OEM in new’ish German cars. It’s been holding up great so far, and now I keep a roll around for many repairs in the engine compartment. I had to re-wrap everything down to the A/C clutch recently.

 

Just curious how easy is it to remove once it has thermal cycled for a few months ??

 

Yeah, forget what I said and do what 1996TacomaV6 did. That should take care of it!

 

I had to get into it to replace my camshaft position sensor connector after it had been installed for maybe 4 months. It was easy to cut a slit down it with a sharp knife and peel it open. I think I would use a hook knife next time to avoid damaging the wire. You definitely can not unwrap it, it sticks to itself really well.

One option if you think you need to get into it later is to put the wire in split loom, and then wrap that with the tape. I did that for the power steering pump sensor and AC clutch since you need the wire to have some strength to stand on its own down there.