Fan Clutch

Topic: Fan Clutch (Read 9807 times) previous topic - next topic

Fan Clutch

June 17, 2015, 06:24:56 PM

Back about 20 years ago or so, my fan clutch went up in my 87 3.8L Cougar. The odd part was the symptoms were backward to me. The engine temperature was fine at idle and low speeds but started to climb at higher speeds. But a replacement fan clutch fixed it. 20 years later, same symptoms. Sanity check: when these fail, does that seem logical?

Fan Clutch

Reply #1 – June 17, 2015, 09:22:42 PM

If you wanted to could grab an electric fan and fan controller. Then youd never have to worry about a fan clutch and you eliminate a mechanical load from the engine.

Controller: http://www.ebay.com/itm/Flex-A-Lite-31147-Adjustable-Electric-Fan-Control-Kit-/131481632186?hash=item1e9cea7dba&vxp=mtr

Fans: just grab one big enough to cover most of your radiator. Most of them come with plastic zip-tie-esque things to hold the fan to the radiator

Just an option for ya

-Kyle

Fan Clutch

Reply #2 – June 17, 2015, 11:27:06 PM

It might depend on just how it fails...cruising at a constant speed, torque converter locked, in OD, the fan should be basically pointless. Add extra load of A/C, hard acceleration because racecar, hilly terrain etc then the thermal strip engages the clutch if needed. But at idle the fan might keep up with the shaft simply due to the viscosity of the fluid inside.

The only thing I know for sure is don't ever buy a non-thermal fan clutch. Absolutely useless, I'd like to know why they even exist as available for these cars...

Fan Clutch

Reply #3 – June 17, 2015, 11:52:31 PM

Quote from: Cougars 2 go;448949

Back about 20 years ago or so, my fan clutch went up in my 87 3.8L Cougar. The odd part was the symptoms were backward to me. The engine temperature was fine at idle and low speeds but started to climb at higher speeds. But a replacement fan clutch fixed it. 20 years later, same symptoms. Sanity check: when these fail, does that seem logical?

I had a fan clutch fail on my Thunderbird. It would be fine cruising on the highway but stop and go traffic or idle would cause the temp to creep up. If you're replacing the clutch about the best one around is the Mustang SSP (police) fan clutch. That's what I run on my Thunderbird. They are discontinued and hard to find now however.

Your symptoms sound more like a clogged radiator to me.

Fan Clutch

Reply #4 – June 18, 2015, 12:51:40 AM

Most factory electric fans don't even come on once the car reaches about 40mph, and when i swapped in my taurus fan, it almost never came on over 25mph. The taurus fan was a super easy swap, but it basically requires a 3g alt upgrade and i burnt out two fan controllers, one was rated at 20amps, the other was rated at 35amps and the fan pulled a peak of 16 amps on start up and 11amps under constant high speed.

I am actually driving my car right now with NO electric or mechanical fan in 95* weather right now. It never overheats on the freeway, but i can't let it idle for more then about 10 minutes once its up to operating temps before it gets to the red.

If i shut my car off as i wait in a drive through or stop and go traffic, it also doesn't overheat and i can cruise ll day long at 25mph without the car getting to the half way mark.

My guess is also clogged radiator or bas thermostat. If its a bad thermostat, generally it will get up to operating temps very quickly and stay there at idle or slow speeds and load. The longer the can runs and more constant load on the engine, the higher the temps go imho.

Fan Clutch

Reply #5 – June 18, 2015, 07:10:10 PM

Quote from: Cougars 2 go;448949

Back about 20 years ago or so, my fan clutch went up in my 87 3.8L Cougar. The odd part was the symptoms were backward to me. The engine temperature was fine at idle and low speeds but started to climb at higher speeds. But a replacement fan clutch fixed it. 20 years later, same symptoms. Sanity check: when these fail, does that seem logical?

Makes no sense. The failure may have masked some other shortcoming of the system (clogged radiator, etc).

Fan Clutch

Reply #6 – June 18, 2015, 07:26:11 PM

Quote from: JeremyB;448998

Makes no sense. The failure may have masked some other shortcoming of the system (clogged radiator, etc).

THIS.....

Looks as though Rockauto specs the same part #'s for the 3.8 and the 5.0

Wanna upgrade on the cheap without hunting for an SSP?

Hayden part #2783 or Imperial part #215130. It's a "severe duty" unit. They're spec'd for a 1991 Dodge Dakota 4WD with the 5.2 V8. Advance auto carries the Imperial brand. Both Imperial and Hayden are the same company.
Should run under $60......

I put one on my Mark VII. Ran perfect in stop & go traffic on the dreaded Belt Parkway in Brooklyn last week.

Fan Clutch

Reply #7 – June 18, 2015, 11:36:20 PM

^^^Interesting!! I will have to grab one of those.

Fan Clutch

Reply #8 – June 19, 2015, 10:28:07 AM

Quote from: Haystack;448966

The taurus fan was a super easy swap, but it basically requires a 3g alt upgrade and i burnt out two fan controllers, one was rated at 20amps, the other was rated at 35amps and the fan pulled a peak of 16 amps on start up and 11amps under constant high speed.

Is the fan you ran a single speed or double? Either way you may wanna check how you measured....

[video=youtube;gWJFzAMsIlc]https://www.youtube.com/watch?v=gWJFzAMsIlc[/video]

When I first read your statement it didn't click, but when I came back and read the latest post I re-read the thread and thought to myself "those readings seem low." Most people use/swap in a 75 or 85 amp relay on the controllers for these things from what I'm reading.

Example: http://www.fordmuscle.com/archives/2003/02/electricfan/index.php

https://bzerob2.wordpress.com/2011/11/15/ford-taurus-2-speed-fan-install/

Fan Clutch

Reply #9 – June 19, 2015, 12:09:23 PM

Quote from: V8Demon;448999

THIS.....

Looks as though Rockauto specs the same part #'s for the 3.8 and the 5.0

Wanna upgrade on the cheap without hunting for an SSP?

Hayden part #2783 or Imperial part #215130. It's a "severe duty" unit. They're spec'd for a 1991 Dodge Dakota 4WD with the 5.2 V8. Advance auto carries the Imperial brand. Both Imperial and Hayden are the same company.
Should run under $60......

I put one on my Mark VII. Ran perfect in stop & go traffic on the dreaded Belt Parkway in Brooklyn last week.

Cool. Whenever the SSP clutch in my Thunderbird s out I'll pick up one of those.

Fan Clutch

Reply #10 – June 19, 2015, 03:07:16 PM

V8 demon

It was a double speed, and i wired of up to only run on high.

I actually have quite a bit of sophisticated equipment designed to measure wattage amprage, peak loads ect. In my opinion, the fan controllers must all way overrated all the controllers.

Lets pretend a mechanical fan takes 1hp, that would be 736 watts. 736 divided by 12 is 60 something amps at 12v's. Electric motors are way more efficient. I have a few model airplanes that produce well over 800 watts and run on a 12.6v nominal system and have specialized equipment to measure loads.

I was very surprised how little power the fan itself took, and how little airflow was required to cool the car off. I have an airplane that weighs about a pound and puts out two pounds of thrust. This airplane uses 24 amps and uses right around 240 watts. The same equipment hooked up to my taurus single speed fan gave me a peak of 24 amps and a constant load of 16 amps, the low speed was 11 amps peak and 8 amps constant.

I find it funny i can buy a brushless pulse width modulation controller rated for 45 amps constant and 60 amps peak for $25 an use it for 5 years, yet a 20 amp fused 35 amp controller burns up under less load in about a month.

In my opinion, the ratings and requirements of all of these electric fans, taurus or otherwise, have been way over inflated by the manufactures.

Fan Clutch

Reply #11 – June 19, 2015, 06:29:41 PM

Quote from: kylesburrell;448955

If you wanted to could grab an electric fan and fan controller. Then youd never have to worry about a fan clutch and you eliminate a mechanical load from the engine.

Controller: http://www.ebay.com/itm/Flex-A-Lite-31147-Adjustable-Electric-Fan-Control-Kit-/131481632186?hash=item1e9cea7dba&vxp=mtr

Fans: just grab one big enough to cover most of your radiator. Most of them come with plastic zip-tie-esque things to hold the fan to the radiator

Just an option for ya

-Kyle

The load is moved to the alternator. Nothing is free.

Fan Clutch

Reply #12 – June 20, 2015, 06:53:56 AM

^ you beat me to it softtouch

Haystack, that vid v8 posted is a "save as" and a good teaching tool *except for the last few words spoken" by the guy doing the vid.

it does a decent job of connecting inrush to load,, two very big points to make out when dealing with motor loads.
spec sheets on DC or AC breakers have curve characteristics, fancy speak for showing what the breaker is capable of withstanding due to its design, it can withstand & is warrantied to do so for the life of the breaker. We call this withstand specs.

some people refer to what the ammeter showed in the vid as initial spike or initial inrush.

if it were me an I had that fan the guy was using, and I had no spec sheets on the relay to tell me anything at all, then I would have saw 30A load and 100A inrush, average the middle ground then multiply x 1.2 to size my over current protection , then round up to the next reasonable / available size breaker and fuse for source power.

cheaper things rated at the same watts may not have withstand specs like more expensive things rated at the same watts..... so the devil is in the details.

another example of best cost vs best price,, I know you know this stuff but I was just wondering about your saying things like this being over rated.

Fan Clutch

Reply #13 – June 20, 2015, 05:09:35 PM

FWIW -- I've often wondered if there was any standardization in the testing done to get the rated CFM of these fans.

Numerous reports for the Taurus fan claim 3000 cfm and 4000cfm or mor for the Mark VIII fan. I'v also seen reports that debunk those numbers and claim much less (although there are far fewer of these).

The reason I ask is due to this:
http://www.summitracing.com/parts/fms-m-8c607-msvt/overview/year/2013/make/ford/model/mustang

Quote

Maximum Fan CFM:3,286 cfm
Fan Quantity:Single
Number of Blades:7 blades
Blade Material:Plastic
Blade Color:Black
Shroud Color:Black
Shroud Material:Plastic
Air Conditioning Relay Included:No
Mounting Brackets Included:Yes
Mounting Hardware Included:No

This is the stock unit that Ford installs in the 2013-14 GT500. Note the CFM rating, which one can guess comes straight from Ford. It's a drop in replacement on all S197 chassis Mustangs.
Ford engineered this thing and figured it to flow well enough on a car with 660+ crank HP that they KNEW people were going to upgrade.

I wonder how large the shroud is on this in relation to the Taurus and Mark VIII setups?

Fan Clutch

Reply #14 – June 20, 2015, 08:29:22 PM

fans are rated and tested with them placed into a tubular front / rear adaptor , same diameter suction as exhaust.

the ration of air moving in to the exhaust with no obstructions,,

anytime air is pushed into an area like a 12'' x 24'' duct work ,, and there is a bend,, this is called static loss. Each time the air has to turn is a static pressure loss.

If you have a box fan at home and you take a piece of plywood and put it in the exhaust path, you can "hear" the motor react. same goes for blocking the intake side of the box fan.

that's all these are is box fans....
now with the rad core & ac core up front restricting air,, and that restricted air is further bouncing back from hitting the motor,,, I would guess real "installed" cfm is 50% name plate rating.