I understand your desire to clean the engine. Some jobs are enough of a challenge without dealing with dirty greasy dusty mess every time you touch something under the hood. However you should take extreme caution in how you do it if you have suspect wiring.

I wouldn't do it at the car wash. If you have crumbling wiring there's a decent chance that the car won't start or run corectly afterwards. I learned this the hard way on my '82 240 and that was with a low pressure garden hose. Better to do in your driveway, where you don't need a tow truck to move it...

Since you're already talking about removing the intake manifold, could you use that opportunity to refurbish the wiring harness? Did you use an aftermarket breather box or did you clean the original? Based on recent discussions here on the board, if an aftermarket replacement was used you may want to inspect it for cracking along the seam while you're in there.

Best of luck,
-Will
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