OK....OK.....OK... I've heard all the pros and cons about the constant running of the electric fan/s (I have only one). Tell me this..... I live in Florida. If the A/C is on all the time anyway (OK maybe 90% of the time. What is the difference, the fan will be running 90% of the time in my case anyway. SOOOOOOOO I think I should wire it so it runs constantly. I've got a 170* stat, wired to be on all the time and I love it. It, the engine, runs soooooo much cooler, that I really don't believe it. Yes when it's really hot AND the A/C is on, the temp raises some, but nothing near the temps when i had a 195* stat and the ECM decided when the fan should turn on. If you live in a HOT area my vote is to wire the fan so that it is on all the time.........Comments?????

 

you know, hot engines have many advantages over cold ones. Emmissions, mileage, wear ( condensation comes out of the oil easier ) more complete combustion. better clearances etc. so long as the car doesn't actually go over 220 or so your fine. Its better for power to run a little cooler, but mostly because the Fuel air charge stays denser. Nascar guys run at 220 all day long

 

Of course a 170º thermostat will let the motor run cooler than a 195º stat.....

That's not a very soild reason to have th fan run all the time.

It was 95-98º here today and even in mild traffic, I never turned my fan on, on my camaro. It's rare I have to. The car has run so hot before it's made the temp gauge stick high (bud's g/f drove it one night..), I even drove it roughly 5mi w/hardly any water in it w/o it even being phased. Right now the clock is ticking close to 300k on it's 305. I'm fairly convinced that temp is not as big of an enemy to a motor as some proclaim. If it were.. I should have shot my camaro well over a year ago... but, that's just my opinion.. bla bla bla

 

A 170* Stat does not mean that it will run at 170*. With out the fan to cool things down it can, and will run upto and at the 220* temp until the fan comes on, and even at that it will never see 170*again. Plenty of tech articles on the subject. My comment was concerning the constant running of the fan. With the A/C running 90% of the time, the fan runs 90% of the time anyway. The car maintains a constant 185-190* with the 170* Stat and with the fan running constantly. Any additional wear and tear on the fan is minimal. Any additional amp draw would be the same and more with the A/C on 90% of the time anyway. I vote to wire the fan on all the time if you live in a HOT climate.

 

LOL.... you bring up an interesting point Ebby. A/C all the time..... fan all the time.

Technically you have mentioned 2 of 3 drawbacks. Shorter fan life, increased electrical load (alternator and battery life) and longer warm up time to normal op temp.

HOWEVER

Add them all together and they still cost a lot less than a fried engine. I think your biggest worry should be when you might have to replace that A/C compressor.......... ya' know.

BTW the stock fan turn on temp is 234° which is basically useless and more of an "emergency" measure.

 

For those that may not know:

Thermostat sets the MINIMUM temp the engine will run at, too cool is no good.

the fan switch sets the MAXIMUM temp the car should reach provided that the fan moves enough air, and the radiator dissipates enough heat.

The water pump circulates the coolant through the block, haeds, intake and radiator. It creates pressure inthe block that helpd to prevent air pockets from forming in the recesses in the block and heads. A higher flow pump can help eliminate hotspots because it should be able to create a little more pressure and flow.

The radiator (heat exchanger) removes the heat from the coolant. It should ( maybe this is my opinion ) be able to dissipate as much heat as the engine can generate, this is a function of horsepower.

Air flow varies, cruising at 70 mph in OD should bring the coolant temp down to the thermostat temp. If not you have a problem.

Electric fans are more efficient, there is a parasitic loss only when it is operating as opposed to a Flex fan the takes HP all of the time. At high rpm you are generally moving at a fair speed so the air the flex fan moves is un neccesary.

BUT, if you run say stop light to stop light your electric fan becomes critical because it has to be pretty powerful to dissipate the heat from all of that HP. A flex fan is better for High HP driving at low speeds.

Hope this helps some of you.

Also, the reason that the electric fan runs all of the time with the AC on is to move air over the condenser so your AC is cold at low speed, it is not neccessary at high speed but its difficult to use a speed signal to turn it off on older cars, i don;'t know for sure but i would guess newer cars with integrated electronic controls might actually turn it off over a certain road speed

 

this is why my electric fan motor will be rebuilt soon and it will be modified to be a whole lot more powerful so that it can move some air

 

Laiky.... it may be the way we look at things but I respectfully disagree on a couple of cooling theories you present.

So we are on the same page consider a stock 195° thermostat in a stock 5.0 engine.

The thermostat can't "set" any temp. It is a dual temperature device in that it opens at one temp, closes at another, and can have a 20° range in between and a +/- 3% margin of error. The stat provides a range of temperature to ideally keep the engine at normal operating temp.

It's primary purpose is to close and decrease the fluid capacity in the cooling system to decrease the time it takes to reach normal op temp. In an ideal situation you would be able to remove the stat and operate at normal temp BUT in a cold climate this would not happen so the stat kicks in and trys to keep the temp in operating range. So it's secondary purpose is in a colder climate to "reclose" and bring a too low temp back up to op temp.

The fans (electric) kick on at 234° which is an emergency measure to bring an engine on it's way to overheating down to normal temp or prevent the engine from overheating when increasing the load (A/C operation).

The electric fan is more efficient when it comes to gas mileage or horsepower, however in most cases the belt driven fan is more efficient at cooling.

I am in agreement with the rest of the good info you have provided.