What temperature is best?

[Ron N]

After a week and a half on my electric fan project, I was wondering what the best temperature is to run the ST at. It has been running a solid 191 degrees after warming up. The fan turns on low for a while at this temperature in town and not very much on the highway. Would it be better to run it at around 185 or is that too low?_Ron

 

[Richard L]

It depends upon what adjustments you have on the Fan thermostat. Usually vehicles that normally run at about 190 degrees will have the fan turn on when the temperature reachess about 215-220, and shut the fan off when the temperature reaches 170-175 degrees.



Those temperatures are based on the coolant in the radiator and assumes that your electric fan control thermostat is located in the radiator or in the top radiator hose (less accurate). This can be hard to measure since the engine temperature sensor is usually located in the intake manifold on the engine side of the engine thermostat.



The easiest way to check is to use an instant-read thermoal laser gun, but you can also use temperature sensitive marking crayons that change colors when a specific temperature is reached. You just draw a line on the radiator with the marker and when the specified temperature is reached the mark will change colors. You will need a marker for 175 and about 215 degrees for your lower an upper limits and the fan should turn off and on about the same time as the marker colors change.



The instant read thermometers are much more accuarate and the prices are getting much cheaper (under $50) and can be used for checking other temperatures in many other applications.



...Rich

 

[Todd Z]

the stock t-stat is a 195.... the truck should not go above that..... IF you go too cold the computer will also think it is too cold and not control air ad fuel properly... 185 is the best for racing 195 is the best of emissions and MPG....



I think your 191 is dam close to perfect....



where and how are you reading the temps from.. the coolant sensor in the truck ?? or an aftermarket reader ?



Todd Z

 

[Jeff C]

I have my fan come one at 195 and it goes off at 185. I am currently only running the low side of the fan, and it is an instant on kind of deal, no variable speed. I'm planning to get a variable speed setup and just hook that to the high side of the fan. Went for a drive around town in the middle of the day yesterday (only 75 degrees and sunny) and the temp never went above 195. Once the real southern summer gets here I'll need that baby running full.

 

[Josh Langel]

Why do you need an extra fan to cool the engine? What are you pulling/pushing/hauling that you need something like that?

 

[Tom Schindler]

The thermostat opens the first time at about 201 degrees and is designed to run at 191 degrees.





Tom

 

[Jeff C]

Mud Flap, the electric fan is a replacement for the clutch driven fan. It reduces parasitic drag on the engine, frees up a few HP, some torque, and increases gas mileage.

 

[Josh Langel]

Mud Flap, the electric fan is a replacement for the clutch driven fan. It reduces parasitic drag on the engine, frees up a few HP, some torque, and increases gas mileage.

Oh, never knew that.

 

[Ron N]

Todd, I am reading off the sensor using a scangauge 2, The highest it usually reads is 203 before it drops. I worked for a long while in the driveway setting it to keep it at 191 on low speed. But I was not sure if it should run it down somemore. In the last 3 days I set a new record driving home from work at 21 mpg. While setting the temp I dropped the gas milage to 13.5 and it is now up to 15.1 So the next tank is the test tank. Jeff, The only thing about the variable I don't like is that it turns on the high speed first and then drops down. If you want email me and I will give you the list of the relays and tstat setup I have._Ron