*I clean the valley out before I replace it if it's particularly bad and then do it after.
*I use degreaser and pressure wash it, I dont see the issue, obviously you don't sit there spraying sensors etc and then leave it to dry.
*The most common one is the oil pressure sensor (tall with a green plug on the end) that one is prone to needing a spray with some electrical cleaner.
*You can give the plugs (while connected) a spray with silicone spray before you wash it.
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