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Parasite noise, m110 engine.

Started by shaggy, 18 April 2017, 04:34 PM

shaggy

I was talking to a French guy on the telephone today, a fellow who is passionate about the w116 and who has 5 of them at any one time. I mentioned how my left hand drive 280SE sounds mechanically unrefined from inside the car and he told me to check the heat shield under the rear exhaust manifold that protects the starter motor wiring from frying. It bolts into the manifold casting in three places and the lower fitting, by nature of the shape and angle of the shield, traps condensation and rots the shield around the bolt, leading to unwanted vibration and resonance. I checked mine and sure enough, that was the case. The solution is to refit with a broad washer of ample enough width to trap the corroded metal but in my case the bolt head sheared (of course!) so I welded a short length of mild steel to the shield, with a hole drilled and bent in order to fix to a neighbouring manifold-to-downpipe bolt.

The result is a much quieter driving experience and less of the 'busy top-end' that I had previously associated with congenital valve noise, so thought I'd post on here because it's something I'd never have sussed in a million years by myself (although I don't know if the same plate is fitted to right hand drive cars).

Thanks for the tip, Guillaume!

Guillaume C


shaggy