A long time ago, ( In a city far far away) I replaced a Northstar engine in my " just bought used with a rod knock", a perfect '93 Cadillac STS. While the engine was out, I went through everything that would have been hard to reach. CLEANED everything, and detailed new engine, inspected & heat-protect wrapped all fluid lines, and re covered all the wiring.
I can see on my '05 Yukon, the wires near the upper suspension, etc., ..the factory covering was brittle & exposing the wires. Plus, clean-de grease the suspension stuff....