I looked through the tech archives here and there was a p/n for a GM switch that fits a Pontiac Fiero among other things. Supposed to turn on at 198F and has a 3/8 pipe thread that matches the W/P housing.

Went to my local chain store to get one. But their catalog showed it as turning on considerably higher than that, more like 220 or 230. They have a large catalog of fan controller switches with pictures and I spent some time looking through it, but I was unable to find one that had a simple spade lug terminal (or threaded stud), a 3/8 NPT thread, and turned on at 190 to 200 degrees... most are M16 (metric) threads!

So can anyone suggest a different switch? I don't want to use the ones that sneak under the radiator hose at the tank nipple - looks like an invitation to a leak or other failure.

Or alternatively, confirm that the Fiero switch is the right one for the job and the clueless counterperson's computer is wrong?

thanks
Charles

There are fan controllers that place the temperature probe between the radiator fins, my personal favorite is the Derale #16759, the turn on temp is adjustable.

http://www.summitracing.com/parts/DER-16759/

I have a Perma cool adjustable that threads in, check summit racing.

Thanks, I have been browsing Summit this evening. They have Painless Performance #30111 listed for hefty $35, on at 185, off at 170, 3/8 NPT thread. Unfortunately a bit too low for my 180 thermostat (the fan would never shut off as soon as the temp hit 185 since the t-stat would prevent it from ever going down to 170 with the engine running)...

But a bit of research on Painless' website shows their #30110 (which Summit also sells for $37.88 although it does not come up on Summit's search engine for some reason) is perfect - 200 on, 185 off.

I was hoping to find the same switch for a more reasonable $10 or so at a chain store rather than marked up to $40 by the aftermarket companies... but as you know their systems are only set up to search by year/make/model and I got cross-eyed leafing through the Borg-Warner and other catalogs without success, as I posted earlier.

Now I'm thinking of just ponying up for a Hayden 3651 ($46 at Summit) which uses a thread-in temp sensor, fully adjustable from 160-210, comes with a wiring harness and a relay too!

-Charles

I went through about 2 or 3 of those switches that have set on/off temps and all three of them (two different MFGs) didn't turn on until 10* higher than what they claimed. I tested them all in a pot of boilingwater with a DVOM and a temp probe.

Then I tried the Derale adjustable unit which is nice because you wait until your car gets to the temp you want the fan to come on and then adjust it so the fan comes on at that time. It works great except for the fact that it doesn't turn off lol. I gave up and just have a kill switch for it.