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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
1988 Firebird 305 TPI.
I have a sensor above plugs 6 and 8 that was previous identified as a knock sensor. I am in the process of taking it out and stopped as it looks nothing like the knock sensor I purchased except for the end. I am not sure the knock sensor I bought would fit because of the heat shield. I found the wire dangling when I changed the plugs. The end had the mushroom type plastic outer ring and a tube connector look just like the knock sensor. I didn't want to take it all the way out as I know I will be getting about 3 gallons of antifreeze out of the engine.
You are correct, it's the fan switch. It does indeed have the same style of connector (single-pin round Weatherpak) as the knock sensor.
It's a damn shame about the coolant coming out when you change it, butt It Is What It Is. Can't replace it without taking it out, and can't take it out without the coolant falling out afterwards. So, yeah. Your radiator fan won't work right without it so you're kinda stuck with it.
The knock sensor is actually the block coolant drain for the pass side of the engine. There's a regular pipe plug on the other side. Both used to be just plain regular pipe plugs until computer controls were introduced. I strongly suggest you remove both, poke out the crust of crud that's likely built up behind them with a piece of muffler hanger (aka coat hanger wire), and take the opportunity to refresh your coolant with a 50/50 mix of distilled water and plain green antifreeze, and of course put in the new KS. Replace any hoses that look old and/or compromised (soft, bulged at the clamps, etc.) especially the radiator ones, the radiator cap with just a normal one NOT the kind with the lever, and maybe even the water pump at the same time. IOW refresh the cooling system all at once so that you don't have to drain it again next week when the next thing fails, as always seems to happen.
