1984 T/A 305 - 150 hp + QJ. Does anyone know at what temp the original fan clutch kicks into operation?

 

Most GM clutches will fully engage when the air temp hits ~210F. The will progressively tighten up starting around 140F. Air temp, not engine temp. With the ac on, it will engage at a lower coolant temp because of the added condenser heat.

 

Tkx Fast355. I sort of figured that. U answered my question.

 

I discovered mine engages full at around 230* coolant temp: was climbing a steep,long grade in hot weather when temp started creeping up...got a little over 230 when a roar was heard underhood and temp shot right back down to 190 and fan noise subsided HD fan clutch from a cop car '83 impala.