Electric fan temp setting clarification

[opfor2]

Hi all,

I recently installed the Flex-a-lite dual 13” electric fan set up in my 90 Blazer w/a stock 350 eng. The instruction sheet that was included was really not much help in explaining what the proper temp setting should be. Presently, I have a 195’ stock temp thermostat installed. I hooked up my OBD1 code reader to see what the ECM was seeing as far as temp goes. Right away I noticed that the stock temp gauge and the ECM temp were different. The ECM temp would show 197’ while the temp gauge would show 210-215’. Should I set the temp on the fan’s control box to what I see on the OBD1 reader or the gauge?

Secondly, should the setting be that of the thermostat at 195’ or higher? I’m confused about what setting I should have the fan come on.

 

[dyeager535]

Fan temp should be higher than thermostat...otherwise you just run around with the thermostat open and the fan running.

I'd be inclined to believe the ECM temp sensor rather than the stock gauge, but you'd have to test the engine temp with a calibrated gauge to know for sure. Either way it's not too hot, if it's consistent I'd live with it.
If the thermostat is a stock 195*, whichever reading is closer (ECM in this case) to that is what I'd go off of. You coudl try cleaning the stock gauge connector, make sure it's in good shape, etc., but likely not going to resolve the issue that easily.


Still if the stock gauge goes over 220*, I'd consider doublechecking things.

 

[opfor2]

I recently replaced the ECM temp sensor, but only cleaned the stock temp guage sensor. I'm inclined to use the ECM reading cuz that's what the computer is seeing and the TBI will act accordingly. So I'm going to try and set the fan control unit to turn on at 200' at idle. That's warm enought for the smog junk to work but still cool enought to keep the eng happy.

 

[dyeager535]

A couple other things to consider is the load on the charging system, and the cycling rate of the fans.

If you set the fan on/off temp a fair amount higher than the t-stat temp (say 210* for instance) your fan will theoretically cycle less which is a good thing. Just watch and see how you like it at whatever temp you decide, and adjust as necessary.

 

[opfor2]

A couple other things to consider is the load on the charging system, and the cycling rate of the fans.

If you set the fan on/off temp a fair amount higher than the t-stat temp (say 210* for instance) your fan will theoretically cycle less which is a good thing. Just watch and see how you like it at whatever temp you decide, and adjust as necessary.

Is 210* ok for the eng? That seem a little hi.

 

[dyeager535]

GM didn'r run theirs on the Camaro (5/5.7L) until 220*. Secondary fan switch wasn't until 240*. 210* is nowhere near too hot.

 

[opfor2]

Kool, I used my OBD 1/2 reader and set the temp for arounf 205* I just replaced the rad. so it's runnung real cool while driving. I'm happy with the e-fan so far. I guess the real test will be this summer and my desert trips in the Mojave with 120* heat =)

 

[d'cheat]

Do your electric fans have thier own temp probe for the radiator?
A little trick for ya. If you have this probe, insert it as close to the inlet as possable. *Upper left side*
Now, the radiator will allways be a lower temp than the engine. Meaning, your engine will be running at temp, however the radiator temp will be lower than that. So if your engine likes to run about 200 deg. then set your fan at 180.

Little tidbit I got from BlackMagic fans.

Later
D'cheat

 

[opfor2]

Do your electric fans have thier own temp probe for the radiator?
A little trick for ya. If you have this probe, insert it as close to the inlet as possable. *Upper left side*
Now, the radiator will allways be a lower temp than the engine. Meaning, your engine will be running at temp, however the radiator temp will be lower than that. So if your engine likes to run about 200 deg. then set your fan at 180.

Little tidbit I got from BlackMagic fans.

Later
D'cheat

Thanks for the info, I've set my fans control box to about 205*. The fans don't come one while I'm driving unles the AC is on. I just replaced the radiator and i have noticed that while i'm driving there is plenty of "RAM" air to cool the radiator to just below the 210 mark on the guage.