Radiator Fan Switch Replacement Question

[donerehart]

Hi Spider Team,
I need to replace my radiator fan switch on my 76. Is there a way to do that without draining all your anti-freeze? Any tips for this?
Thanks,
Don

[fiat218]

unscrew and screw fast

[RRoller123]

Gunna have to drain it I think, no way I know of to get around that.

[spider2081]

I think if the radiator cap is sealing correctly and the engine is cold you should be able to remove the cooling fan switch and replace it with very little coolant leaking out. There should be no way for air to enter the system if the radiator cap is good so almost no coolant will should come out. Like putting your finger over a straw.

[RRoller123]

Nah, the hole is too big, air leaks past. The surface tension can't stop it.

[klweimer]

Maybe if you flip the car over on it's top, so the fan switch is at the top of the system?

[fiat218]

you could unscrew that plug quick and get a new one in there before a quart comes out. i will bet on that

[JohnMc]

drain into a clean container and put back in.

[DieselSpider]

When I faced this quadry the additional issue of how much torque would be required to unscrew the original switch potentially damaging the lower radiator pan causing leaks became a concern so I purchased the external adjustable universal switch from Advanced Auto Parts for less than $20 and just bypassed the original.

Most stores don't realize they even have them in stock but can find them on the shelf out back. I strapped the sensor to the upper radiator hose with a few zip ties since I did not want to chance causing a leak when pushing the mounting straps through the fins in the radiator and it works just fine. Added the Lucas version of Water Wetter to the coolant while I was at it and have no problems even when roadway temps are closing in on 120 degrees.