Thermal fan switch and thermostat combo - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MYOUNG · 06-27-2017, 04:12 PM

I Just finished installing my electric fan conversion on my near stock 69 GMC 2500. I used the 1995 ford Taurus fan with a single stage controller kit from Amazon and electrically everything works great. My question has to do with the correct temperature of the Thermostat VS the Thermostat fan switch. Currently I have a 160F thermostat and a 185-170F fan switch. The problem I am seeing is that once the fan comes on, it does not really turn off. I would like the fan to cycle as needed and not run all the time because the cut off is close to the Thermostat temp. What temperature fan switches / thermostats are you guys using?? I have seen 190-185, 200-190, 195-185 etc.

The fan switch is currently mounted in the 3/8" port at the front of the intake

BTW I managed to use my original fan shroud with the new fan. I rear mounted it from the inside with 1/4" spacers and still looks stock. There is about a 1/4" gap between the water pump pulley and the fan motor.

**HO455** · 06-27-2017, 06:24 PM

My guess is that your water temp is not dropping below 170. Why did you go with the 160 thermostat? That is pretty much a drag race item. 180 is more appropriate for a daily driver. My dual fan setup is 1st fan on at 195 and off at 185 and the 2nd fan on at 210 and off at 190. When the outside temperature is in the seventies the 1st fan is almost always on and the 2nd one cycles on and off in heavy traffic. Winter time the 1st one shuts off on the freeway and the second one rarely comes on.
Please post some photos of your fan installation..

MYOUNG · 06-27-2017, 07:03 PM

Thanks for the response HO455

I am running a 160 because an older fellow at the parts house told me that "originally they had 160s in them but now folks use 180s". I could switch out both the Thermostat and the Temp switch but I was thinking that I would run a slightly higher temperature fan switch.

I guess I didnt know what to expect. Perhaps the fan running continuously with around town driving is normal.

I could wire a second temp switch in the passenger cyl head that would turn on the high speed side of the dual speed motor?? Right now I am only using the low speed side.

I will see if I can add a few pictures later on when I am back at home.

Cheers

06-27-2017, 04:12 PM	#1
MYOUNG Registered User Join Date: Jul 2016 Location: antioch CA Posts: 29	Thermal fan switch and thermostat combo I Just finished installing my electric fan conversion on my near stock 69 GMC 2500. I used the 1995 ford Taurus fan with a single stage controller kit from Amazon and electrically everything works great. My question has to do with the correct temperature of the Thermostat VS the Thermostat fan switch. Currently I have a 160F thermostat and a 185-170F fan switch. The problem I am seeing is that once the fan comes on, it does not really turn off. I would like the fan to cycle as needed and not run all the time because the cut off is close to the Thermostat temp. What temperature fan switches / thermostats are you guys using?? I have seen 190-185, 200-190, 195-185 etc. The fan switch is currently mounted in the 3/8" port at the front of the intake BTW I managed to use my original fan shroud with the new fan. I rear mounted it from the inside with 1/4" spacers and still looks stock. There is about a 1/4" gap between the water pump pulley and the fan motor.

06-27-2017, 06:24 PM	#2
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,351	Re: Thermal fan switch and thermostat combo My guess is that your water temp is not dropping below 170. Why did you go with the 160 thermostat? That is pretty much a drag race item. 180 is more appropriate for a daily driver. My dual fan setup is 1st fan on at 195 and off at 185 and the 2nd fan on at 210 and off at 190. When the outside temperature is in the seventies the 1st fan is almost always on and the 2nd one cycles on and off in heavy traffic. Winter time the 1st one shuts off on the freeway and the second one rarely comes on. Please post some photos of your fan installation.. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

06-27-2017, 07:03 PM	#3
MYOUNG Registered User Join Date: Jul 2016 Location: antioch CA Posts: 29	Re: Thermal fan switch and thermostat combo Thanks for the response HO455 I am running a 160 because an older fellow at the parts house told me that "originally they had 160s in them but now folks use 180s". I could switch out both the Thermostat and the Temp switch but I was thinking that I would run a slightly higher temperature fan switch. I guess I didnt know what to expect. Perhaps the fan running continuously with around town driving is normal. I could wire a second temp switch in the passenger cyl head that would turn on the high speed side of the dual speed motor?? Right now I am only using the low speed side. I will see if I can add a few pictures later on when I am back at home. Cheers



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