I should have listened when The Actual Rootwyrm advised me to throw the Haynes manual in the trash.
I’ve concluded that my knock sensor is fried because I cannot get any resistance reading between it and ground. So last night I picked up a deep 7/8” socket and a replacement. I double-checked my Haynes manual for removal procedure, and it’s pretty much “remove the distributor if it’s up top, then remove the sensor.”
So I go crawl under the truck since mine is below my exhaust manifold, and get to removing the stubbornly wedged-in sensor without a breaker bar (because my only one is 3/8” drive and the socket is 1/2”). After a few minutes of whacking the wrench handle alternated with pulling as hard as I can, it begins to turn.
I’m feeling very pleased with myself because I was worried I would not be able to get it off, but that feeling turns as soon as I pull the sensor out and I’m rewarded with ... coolant flooding out of the hole!
After 15 seconds I manage to get the sensor back in, but now my glove, arm, and shirt are thoroughly soaked with coolant. I take my shirt off and use that and some rags to mop it all up the best I can, spray the rest down with water — as we said at the nuclear reactor I worked at, “dilution is the solution to pollution” — then go clean myself up.
After I’m no longer covered in ethylene glycol, I do some searching on the internet and discover that, yes, coolant coming out of this hole is expected, so you should either drain the engine or be prepared. Thanks for nothing, Haynes Manual. I’m now seriously considering forking over the dough for the factory service manual.