i now have a 200/185 fan switch in the car. it wants to come on at 180. i had a 180/ 165 fan switch that came on at 160. why is my fan coming on twenty degrees before it is suppose too?

 

What are you using to tell what the coolant temperature is? The stock temp. gauge in the dash?

 

i used a themometer in the radiator.

 

I couldn't tell you exactly why that's happening, but I do have a suggestion. Since the fan switch is in the cylinder head on the block, you can check and see if the coolant temperature sensor (CTS) or the coolant temp. sending unit is reading the same temp. as the fan switch.

Try this, start the car and let it warm up until the fan kicks on. Immediately shut the car off and disconnect the wiring from the CTS (the CTS is located in the thermostat housing on the earlier 3rd gens, IIRC). Use a multimeter and check the resistance between the 2 pins in the CTS. Check it to see what temp. the CTS is reading. You can do the same with the coolant temp. sending unit if you want (located in the driver's side cylinder head in between the #1 and #3 spark plugs). Just attach one lead of the multimeter to the end of the sending unit and the other lead to a good ground. Should get pretty much the same reading.