i have a 89 gta with 350tpi i put a new 180*thermostat and it runs around 220. what do i have to do to use a hypertech fan switch?

 

take out your stock one and put that one in

 

to install the switch al you need to do is get a ratchet, with a 3/4 (i think) or 7/8 socket. try to use a swivel or somthing on it its a tight spot. the switch is slightly lower and between the 6 and 8 spark plugs in the block. Dont use teflon tape, just make sure you tighten it down good. and just slpice the new connector in. the old one is prbably pretty brittle from heat.

 

As said before, go to NAPA . They carry two different ones. The stock 238, and one around 210 or so. They cost $19 and are the very same thing as the performance ones.

 

what kind of a car is the 210 switch for? the OE switch is 240 for the dual fan setup. The after market ones are all 200. and I've been looking for a ~210 switch.

 

I went to NAPA and the guy told me he had 2 different ones. I wanted the stock 238 for secondary control. I am going from memory but I thought the lower one was somewhere around 205-210. Mine is an 89 iroc, 5.7 tpi if it helps.

 

just curious,why would you want the 238 for the secondary?

although my 89 is still all stock, and hardly gets to the secondary fan. 222 is the computer controlled first fan.

The problem is and people don't realize this. starting in 89 or possibly earlier, the ECM knows when that 2nd fan is on, and will turn on the first fan.

so if they throw a 200 fan switch in there, both fans will run or no fans will run. you basically are defeating the primary fan.

 

Yup, I found that out. There is a wire that goes back to the ECM and tells it if the sec fan goes on. The ECM then defaults and turns on BOTH. You will find this in some of my other posts. I chose the stock 238 because I don't want them cycling all the time. It places undue stress on the charging system and relays. I have a zz-4 block and all new OE cooling components. With an entirely stock temp control at 101 degrees yesterday in normal stop and go it runs just below the 220 mark. Can't ask for anything better than that. Personally, I think oil and oil temp is more important than 10 or 20 degrees coolant temp anyway. The coolant temp constantly changes faster than the sender and guage react. Me thinks synthetic oil will add longevity much more so than fussing around with OE operating temps. Just my 2C

 

2 ways to think of both fans turning on at once. totally unneccessary ,........ or if you turn the AC on, both fans will turn on at once anyway. once the AC head presure hits a certain point that is.

so my fan temp switch is still stock. the single fan usually handles it at 222 when it comes on, or I run my AC which still works great after 13 years

the real solution is the ECM turning on the primary fan at 190. or leave it stock like me and I still have some OE heater hoses that havn't failed yet.

 

I may be confusing you Larry, the 238 is the fan switch for sec fan operation. It has stock ECM Prom settings for primary control. I believe the reason NAPA stores show 2 units is because certain 305's do NOT use ECM control for single fan setups. I have GM drawings here that show the single fan controlled by the switch, fan switch in heater/ac assy, and AC pressure switch all wired in parallel with no ECM assistance at all. In those models they probably kick the fans on a little sooner.

 

The simple solution would be to cut the grey/ground wire going to the ECM if you install a lower fan switch.

 

>>>The simple solution would be to cut the grey/ground wire going to the ECM if you install a lower fan switch.<<<

yeah, but you need both fans for the A/C to run.
I guess you would have to cut the wire in the right location, not the one going to the A/C head pressure switch.