I'm going to have to repair a fair bit of cables under the bonnet. I just noticed the oil sender harness is quite short and has two plugs. I will see if I can source one and get the cables replaced in it. The three colours should be stocked at the auto electrician so should be fairly straight forward to fix.
Regarding the oil sender I think I might have figured it out. All the oil that squirted through the cables, unsheathed the one red wire that was soldered and taped and not joined using a solder joiner. It had extra tape on it near the plug, which made me not see there was an exposed lead underneath.
Yes the 26 year old cables have seen better days. They seem ok where conduit has kept them away from excess heat but the short leads that go to various sensors, where there is not even tape covering them has become pretty brittle, especially on the flex points. I'm thinking I might have to do what I can myself, like replacing conduit. I may be going back to the plan of sourcing a damaged harness and using the plugs and any colour coded cables that can no longer be easily bought, like the ones with stripes. But I'm not climbing underneath at the wrecker anymore it's just too risky. I'm not sure how he gets away with it really, probably because it Rural Tas, hahahahaha.