Fan clutch question

[rangerguy98]

I have a 98 ranger 4.0 5 speed 3.73 posi trac, headers, jet performance maf, brute force air intake, BBK throttle body, hypertech power tune and 160 thermostat... I havent noticed anything wrong with truck getting hot or staying real cool. when cold start it fan clutch comes on loud and after bout 2 min quiets down. It always runs cooler because of 160 thermostat ,but when reading online it said fan clutch should spin freely when cold and have some resistance when warm. But mine is the complete oposite has resistance when cold will turn bout 1/4 spin cold and freely when warm. replaced clutch before because of lack of power and clutch wasnt coming on in cold start new 1 has about 5000 miles on it got from advance auto whick i figured would b fine since it is garage kept and barely drove. im just a freak about my vehicals and im always checking for stuff b4 it goes bad lol. Any help would be apriciated!

 

[RonD]

I would say it might be normal in your case.

The fan clutch works from the temperature of the radiator air, not engine temp.
They all cold start "engaged" then will go to the "proper state" after a minute or two.

As the rad air temp gets above 170deg the bi-metal "spring" on the front of the fan clutch expands and causes the clutch to engage the fan more, as temp goes below 170deg then fan is almost in free spin.

Running the 160 t-stat is keeping the rad air temp below engagement.

My personal opinion is to run a 192 t-stat, you get the best engine performance at 200-220deg operating temp, cooling would be the same in that a 160 or 192 t-stat would be fully open at 200deg.
Running an engine at 180-200deg is a waste of fuel, and oil viscosity is measured at 212deg, so a 30w might be closer to a 40w at 180deg.
Nether is a big deal just an observation.
Fuel economy and power is all about mixture and combustion temp, lowering the engine temp means a working ECM would run a little rich to compensate.

 

[rangerguy98]

when i purchased the hypertech tuner they recomended the use of a 180 to 160 thermostat from where the truck might run hotter with the more fuel the tuner would be using so i did a 160 because the summers have been pretty hot and with those 3.73 gears running highway speeds at 70 ur taching about 2700 rpms all the time.I could tell a great power difference between the 160 and the stock thermstat. truck usually runs between the middle mark and the quarter mark except for right now with it being colder run just a lil above the quarter mark. so u think where truck running cooler might cause the clutch the be in a free spin state when hot? Would it still be nomal for it to have resistance when it is dead cold?

 

[RonD]

I am not sure of the low temp "engage" of the clutch, just guessing I would say anything under 80deg would mean "engaged", a few minutes of spinning should increase clutch spring to above 80deg, then you hear it quiet down as it spins free.
Then around 170deg, air temp, it would start to engage again.

A t-stat can only control the low temp of the coolant/engine not the high temp, so a working T-stat can never cause over heating.

Running a low temp t-stat can be done to increase horsepower, the lower the engine temp the lower the intake temp, cooler air mix = more hosepower.
More horsepower = less MPG

Rule of thumb is 5deg drop in air mix temp = 1% increase in horsepower.
This is why you felt an increase in power from switching the 192 to the 160 t-stat, , a 30deg drop, that's about a 6% increase in horsepower, for $10, lol, but mileage goes in the toilet.

 

[shane96ranger]

Running the 160 t-stat is keeping the rad air temp below engagement.

My personal opinion is to run a 192 t-stat, you get the best engine performance at 200-220deg operating temp, cooling would be the same in that a 160 or 192 t-stat would be fully open at 200deg.
Running an engine at 180-200deg is a waste of fuel, and oil viscosity is measured at 212deg, so a 30w might be closer to a 40w at 180deg.
Nether is a big deal just an observation.
Fuel economy and power is all about mixture and combustion temp, lowering the engine temp means a working ECM would run a little rich to compensate.

This....

 

[Sasquatch_Ryda]

And more fuel = cooler, lean = hotter.

Get the proper T stat in there.

 

[rangerguy98]

I actually drove to work all week on $20 that was like 115 miles don't think mileage is doing to bad at all. And that's using super grade fuel

 

[RonD]

I actually drove to work all week on $20 that was like 115 miles don't think mileage is doing to bad at all. And that's using super grade fuel

You found someone with a Toyota to drive you to work all week for $20!!!!
Now that's cool.

lol, joking

Power is always a trade off with lower MPG, just one of those pesky laws of physics, gravity sucks too, the government should do something about both, same old election promises and nothing gets done.

 

[kimcrwbr1]

Not to mention bearing and piston tolerances are all factored into engine temp. You can be setting yourself up to premature engine failure by changing the design temp. IMHO

 

[rangerguy98]

So does anyone think my fanclutch is ok beings that it is backward compared to what the haynes manual says? its harder to turn cold easier to turn warm!

 

[RonD]

Since you are after horsepower I would switch to an electric fan, takes power to turn that fan, even free spinning takes some power.

But, yes, I think your fan clutch is fine, fan clutch going bad will cause temp gauge to go up when engine is under load, like driving up a hill, where air flow thru the rad is the same but engine is generating more heat(burning more fuel), fan clutch is there to compensate(boost) air flow thru the rad when extra heat in the rad is detected.
It can also cause temp gauge to go up and down randomly as it works and fails, works and fails.
Bearing can fail as well, wobbly fan causes a vibration above 2,500 RPM at first, then at lower and lower RPM as it gets worse.


You can always test fan clutch, run engine to operating temp.
Turn off engine, spin fan manually, as you said it spins freely
loosen shroud
Put lighter on spring in the front of the clutch, heat it up
See if fan starts to tighten up
I have never done this type of test.

If you have a surface thermometer you can also test spring temp, below 170deg free spin above 170deg progressively hard to spin.

 

[rangerguy98]

Where can I get n electric fan? Is it hard to install I seen 1 guys post about one sayn that u turned it on when u want it and it dims his lights at night when using it. Seems like it might b annoying?

 

[RonD]

Where can I get n electric fan? Is it hard to install I seen 1 guys post about one sayn that u turned it on when u want it and it dims his lights at night when using it. Seems like it might b annoying?

That would be called a "marginal" installation.

Lights dimming would be a marginal alternator, 1 or 2 of the windings had failed, there are 3 "phases" when an alternator is outputting AC power to the DC convertor, as alternator gets older 1 or 2 of the phases stop working so at low RPM battery is supplying most of the power, if your headlights dim at idle then alternator is on it's last legs.

Electric fan conversion is fairly straight forward.
Remove fan clutch and fan.
Remove shroud, it won't be needed

Install electric fan on Rad, different models have different mounting methods.
Install fan thermostat in or on Rad, I prefer rad because its better in all weather conditions, i.e. cold weather, using engine coolant temp sensor works as well.
The sensors are adjustable so you set the turn on, turn off temp for the fan based on your placement.

I would install a relay and fuse for the fan, the relay would turn on power to the fan when key is on, fuse would be an inline type between relay and fan motor, thermostat still turn fan on and off with temp, but only if key is on, just in case.
Most factory fans are direct wired so stay on after key is off, that would be up to you, if you drive in hot weather then you may want the fan to cool rad for a short time after engine is off, this setup would only need the fuse, and a good battery

You will get better MPG and horsepower without an engine driven fan.

 

[rangerguy98]

Is there a certain brand electric fan kit that is prefered and does it fit specific for my ranger does kit include the fan thermostat

 

[RonD]

Have a look at this How-to

http://www.therangerstation.com/Magazine/Summer2003/ElectricFanInstall.htm

There are a few "kits" that include all the parts you need.

There are also stock electric fans system from other Ford products that can be used in a Ranger, fan, relays and temp sensor, so a stock system but from another Ford model.