Radiator Fans Explained Good Better Best Autorestomod Episode 393

Radiator Fans Explained Good Better and Best Autorestomod Episode 393
The Radiator Fan is the most unsung hero of your cooling system. The fan, be it a clutch fan, fixed fan, flex fan, or electric fan, works to keep your car cool. We look at the fan and why it is important to your car’s health, we look at which fans are good at their jobs. We look at why the Big Three went to clutch fans. We talk about flex fans and why they can be a liability.
/ autorestomod
Thanks for watching!
Jeff Ford Contact:
[e-mail]
Parts:
www.vintageair.com
Monster-duty fan clutch 3.375 IN. Part #: 32001-VUF
Clutch Fan Blade 18 IN. x 2 IN. Fan Part #: 32518-VUF

[@mikedepalmasr]

Three minutes of this is all i could stand, constant talk over one and another

[@AutoRestoMod]

Thanks for the input.

[@moeshouse575]

in 1968 i was in Tulsa at the worlds points finals. i saw a REAL hemi cuda. the guy went to check the timing. he grabbed the fan, a flex fan. and the other guy started the engine and slipper fan did the slipping for him. so he get the timing light in to the engine. and he checked the timing. NO trouble.

[@bennyboyy7]

I like the woosh from the mechanical fans. The electric fans sound like drones. And the mechanical fans are always turning and moving air, I had an electric fan with abd it was either on or off and it would draw quite a bit off the battery. At idle the motor would struggle a little from the fan kicking on. Yes I may have been able to get a different controller with more options for fan controls but the fan wouldnt kick off until I got moving around 20 mph.

[@zackfuetsch4716]

You guys rock! Thanks for the help.

[@stevestraus7291]

For the fan bolt washers I use SAE washers instead of regular cut washers ; they don’t extend much beyond the bolt head.

[@AutoRestoMod]

We try and use the stuff that is readily available (Box stores like Lowe's) so that we can figure out how the average guy shcleping to the store would deal with the issue.

[@DjCBlaq]

New subscriber. You guys do great work.

[@Dexjohnson140]

This helped alot for my chevy monte carlo

[@kennymcquinkiss8292]

You guys are Great. Thank you

[@donpratt9872]

nice thanks

[@wking523]

I have a 68 Torino GT with a 390 ci. All the books that I look at seam to be missing the section that says a 68/69 Fairlane/Torino came with a 390 or bigger when it comes to the radiator and fan shroud. All the other parts you can find just not the cooling parts. I have had the radiator record, but I cant find anyplace that tells me what shroud I need. Any help would be appreciated.

[@AutoRestoMod]

Auto Krafters carries a fan shroud that is for the 390-428 powered Torino www.autokrafters.com/ PN: C8OZ-8146FE The Fan MAY be the one Don Mentioned above: www.npdlink.com/product/fan-blade-assy-exact-repro-7-blade-18/146211/200387 You might also look at the series of clutches that NPD offers for the Mustang. Be sure to see if you can get a depth measurement from the mounting flange for the fan and the shaft base where it mounts to the pulley. Be advised that an aftermarket radiator may be thicker and have interference issues.

[@568843daw]

The inrush of current in a motor always exists because the motor needs to set up the magnetic field in order to cause rotation. You can protect the wire with a fuse that is time delayed to accommodate that. However the wire gauge also must be larger and the wire’s insulation must be rated for the fans and the heat generated within the engine compartment. Since the coolant sensor is turning the fan off and on than the inrush becomes frequent enough to overwhelm the wires’ insulation. That is why you are seeing burned wires.

[@AutoRestoMod]

Thanks!

[@car_ventures]

To help the two issues with electric fans (on/off and initial current draw), there are fan control modules which offer "hi/low" speed and "soft start". Usually a PCM module can make it run at two different speeds, so you could have two temp switches e.g. 195f wired to slow, 210 wired to high, or 195 to slow, then high to a manual switch. The soft start function simply brings the voltage up, over about a second or two, to help level out the initial draw.

[@AutoRestoMod]

That is great information! Thank you.

[@car_ventures]

@@AutoRestoMod All thanks goes to you guys for making these great vids!

[@cutworm59]

The dealership I worked at had a fan recall in 75-76 for fan explosion. Lost 20 lbs Jeff? Looking good .

[@AutoRestoMod]

Thanks, feeling better too. Just ten...the camera remove ten more. Paid extra for the feature. 😄😄😄

[@blastro5631]

I got a 66 Impala coupe with a 283 and AC, currently has a fixed fan but my shroud is cracked on the top and bottom and it’s running hot. I’m going to replace the shroud and hopefully that fixes everything. I only have issues when I’m on traffic so I think the fixed fan is best because it’s always going but I do like the idea of a clutch fan, if I switch to a clutch fan will it be cooler or just save hp?

[@AutoRestoMod]

Depends on a lot of things. I' d make sure that the fan and shroud are correct for the car, if the fan is too deep it won't pull, too shallow, won't pull ether. If you have the correct depth it will.

[@theovallas]

Great episode! I still have my stock fan in my '72 F100. I think I will soon upgrade to the Vintage Air fan & clutch. It's gotta be worth 1 mpg in an FE right??? Or am I being optimistic? HA!

[@AutoRestoMod]

FE will get 8 mpg. Up hill, down hill...parked. 😄😄😄

[@averyalexander2303]

Not sure but my friend swears that his Bronco went from 11 MPG to 12 MPG when we replaced the clutch fan with dual electric fans. Not a bad gain for the amount of work involved, but the expense was tremendous.

[@mikef6706]

What about a clutch fan with a vey rusty thermal spring. Will this affect thermal operation of lockup?

[@AutoRestoMod]

Possibly. I would get a timing light and mark the shaft and the clutch to see if they are turning kind of together when the car is at operating temps. If not you may need to replace the clutch.

[@ronaldkelley3442]

What is the best fan for a 1965 ford falcon Ranchero when a 289 engine it has been bored 40 over has a 302 crank in it

[@AutoRestoMod]

I like clutch fans with at least 6 blades. BUT the thing you need is a fan shroud to make any of them function at top peorformance.

[@tahitipehrsonstudio]

hey @autorestomod what size fan did you use in the F100? I got an 18in and it only leaves 1/4 inch from the shroud on top. Factory was 17.5 should I have gone with the 17in?

[@AutoRestoMod]

As long as it pulls more air, I'd stay there.

[@tahitipehrsonstudio]

@@AutoRestoMod thanks guys!

[@carmelogonzalez8710]

What would suggest for a 1970 ford van e200 want to change the fan and radiator

[@AutoRestoMod]

I'd go with a good quality clutch fan.

[@hughphillips67Mustang]

My set up looks the same as yours. The clutch is about 2, 2.5 inches from the radiator. Yet the fan blades are just inside the shroud. (Just like yours). Is that right? Or should I put a 1 inch spacer on to set in deeper into the shroud?

[@car_ventures]

Just inside is perfect, half to an inch or so is good. As long the clutch side end of blade sits slight within the shroud, it's enough to break up the trailing edge turbulence

[@TheThirdWheel618]

Great episode ...biggest problem I had with elec fan was the draw at a idle at night , the defroster on or heater AC etc the bigger fans or two running at the same time need full amps to flown full speed at idle. I had a 70 amp alternator at around 600/625 rpm a little higher than spec in gear automatic C6 with headlights on heater etc I would drop below 12 Volts on the battery with fan going that effected my elec ignition module that needed constant 12v . I eventually put a 1 wire 140 amp tuff stuff alternator like you have there but then after 1 year the temp control module went out . If you don't have a spare your in trouble on the road unless you wire it to constant 12v on the side of the road there is HP loss with a clutch fan but who's running WOT all the time ???? I seen that episode were they tested those fans If I remember correctly it was more like 3HP loss 30 HP ? That sounds extreme .I have a pusher in front for stop and go traffic and flex fan as well now .

[@AutoRestoMod]

Thanks for the info.

[@castillo33brandon]

Great video, subbed to your channel now

[@markvincent719]

Another great episode...I'm a fan. Haha, see what I did there...welp, I'll keep my day job then.

[@AutoRestoMod]

HAHAHAHAHA...no pursue that comedy career you have always dreamed of.

[@brodiecrandall4491]

I had the bearing go out on my fan clutch and it sent the fan through the radiator

[@piercer2]

Dumb question, but on a ford 302, the fan is supposed to PULL air through the radiator right? As in the airflow going down the road is in the same direction the the fan is sucking the air through radiator?

[@justanjustan9624]

Yes you are correct. In a front engine vehicle, you want the fan to suck oncoming air through the radiator inward towards the engine.

[@piercer2]

@@justanjustan9624 at what road speed does the air speed hitting the front of vehicle exceed the fans pulling air speed? Or does the low pressure differential created by the fan (assuming it’s slower) further boost the overall airflow across the radiator?

[@justanjustan9624]

@@piercer2 This I cannot answer, I'm afraid. I apologize. Is there a particular reason you're seeking these specific details?

[@shyguy2960]

What about fabricate a flex fan and bolt it in the place of the original mounted fan?

[@AutoRestoMod]

Not sure I want to turn 4,000 RPM on a home made fan....

[@gadsdenviper7149]

If you've never seen the video Engine Masters did on HP loss with certain fans, they dyno'd a small block Chevy and the clutch fan caused the least loss of HP @ 15 hp and the fixed fan was like 35hp loss. Electric is the best choice for least hp loss by far. Thanks guys

[@AutoRestoMod]

Yeaaah, we don't have the might of Discovery Channel behind us...so we just glean info instead. LOL

[@gadsdenviper7149]

@@AutoRestoMod what you lack in $$$ you make up in common sense.

[@L-Noble.YT_Hi.Res-Soundminds]

The future is electric. clutch is for the trans. lol

[@hotrodray6802]

Tests have shown that a 65 amp load on a belt driven alternator pulls less than 3 horsepower.

[@optimusprimer4392]

I run a fixed 6 blade in my square body 4 by 4 it is noisy but on 110-degree day I have no issues other than ethanol fuel percolation and vapor lock corns for your belly not gas

[@AutoRestoMod]

Agreed. Our biggest issue in the F100 is gas perk.

[@mycontinental3611]

My 2004 F-150 still uses a clutch fan, Ford went electric in 2009 on the F-150.

[@AutoRestoMod]

Thanks for the heads up!

[@Kana0211]

If a clutch fan locked up because it failed and I rev the engine to 6k rpm would the fan destroy itself and throw blades into the hood and radiator? Its a plastic fan on a Toyota tundra.

[@JeepITguy]

Never have I seen a clutch fan fail by locking up. They freewheel

[@user-cf6ys7kh6g]

Well at least I got 7 blade clutch fan , so that's good

[@gerardomendoza9688]

Brand New 3/4 ton 1 ton pickups still use clutch fans till this day that's very grate. I hate that newer cars V8sedans went to electric fans while pickups with the exact same engine get to use a clutch fan, like. c'mon...

[@AutoRestoMod]

True enough.

[@moparproud3978]

New Ram Cummins still have a clutch fan. My ‘07, I have a dyno graph that shows a 66hp loss at the tires when the fan engaged

[@AutoRestoMod]

Wonder what a flex would do?

[@jimmy450r]

Usually 15% - 20% power loss from crank to wheels is normal. Curious how a clutch fan uses 66 hp to run? You sure you're not adding up the power loss and the fan load?

[@moparproud3978]

@@jimmy450r 15-20% is merely an approximation to get a good guess but is far from a hard number. Newer vehicles for instance have better efficiencies and will never see 15-20% loss. Anyway, back to the question. I’m not adding anything, I literally have a dyno sheet that shows each of three runs; first two were 502 and 503, third run was about 440 or so. I don’t have it handy but it was shocking. The only thing that changed was the fan kicked on, this is all wishing probably 3 minutes

[@tjhamer3]

My 74 maverick with 302 and a\c came with a 7 blade fixed flex fan?

[@AutoRestoMod]

Is that a question or an answer with a question? The big three did some crazy stuff. I wooud say "typically" Ford would have used a flex fan on the Maverick. But when assembly and schedules on the line are at play, there is no telling what might be done. My '72 Mach 1 has '73 Deluxe upholstery so...yeah, sometimes to get them down the line, anything goes.

[@AndrewWallacelive]

One thing I'll add: when you're selecting a fan, do your best to create a mock-up of the fan with the engine fully dressed and the radiator in the car before you actually commit to a certain fan setup. This may require a few calls to tech support lines since certain fan manufacturers don't prominently provide all the dimensions you'll need to know in order to measure correctly.

[@AutoRestoMod]

Yeah I agree. We didn't do our homework on the first clutch we ordered and it came back to bite us.

[@stuckinmygarage6220]

+Andrew - Yup! Doing just that, found a low profile clutch from Hayden 2947 vs. the more popular 2747. Made it just fit.

[@williamcharles9480]

Hey there, Jeff, its good to see you looking well. I have a 67 Mustang with a crate, pushrod 5.0 V8. I initially went with an electric fan set-up and after having continuing issues, which included the quality of a couple of the name brand fans and their components, I called it quits and went with the simplicity of a clutch fan. The electric fan, besides the quality issues, on occasion, would cause my V-belt to slip and squeal when it would engage. It seemed that if the battery was a bit low on charge it would aggravate the problem. I thought about a two belt pulley on the alternator as a remedy for the slippage, but finding the correct pulleys and a matched set of belts was going to be a big PITA. The simplicity of a clutch fan fit the bill for me and the loss of a small amount of horsepower isn't an issue on my mostly street driven pony. What I wanted was dependable cooling for a car that has to live in Florida heat. One thing that folks need to consider is the RPM limit that mechanical fans have on them. Buying a fan that has the capability of safely withstanding the RPMs that they're going to be subjected to is obviously something that seriously needs to be considered. Some fans that I found had a 4000 RPM max. limit on them, but I shopped around and found an all steel, 17 inch, 6-blade clutch fan that maxes out at 7000 RPM. I even called the manufacturer to verify this fact. I know that fan pulley diameter is a factor with fan speed, but I wanted the extra safety offered with the 7000 RPM max limit. I may be a bit over concerned, but I've seen the carnage that a thrown blade can make and it isn't pretty and can even be deadly. You may have mentioned that there's two types of fan clutches, (actually three types with the electronically controlled thermal clutches that I'm not going to get into), there's the cheaper non-thermal centrifugal clutch that's always engaged and spins at about 30% to 60% of water pump speed, according to the RPM and then there's the thermal clutch that stays disengaged until its rated temperature, (about 170* F), makes it kick in. The thermal clutch is the one to have for the fact that it will disengage. This allows for a bit of fuel savings and less loss of power. I know electric fans have their place, especially with front wheel drive applications and where space is a factor and I probably wouldn't have had an issue of belt slippage upon fan engagement with a ribbed belt and tensioner, but at the moment a thermo-clutch fan was the simplest and most economical move for me. Thanks guys for all that you do for me and the hobby.

[@AutoRestoMod]

Nicely put William!

[@Milner62]

Yep, my old 82 F150 has the OEM flex fan that I am not sure if I want to retain. Pulls amazing air flow and makes my converted dealer ac blow 58* even when it's 100* outside. Afraid with a thermal fan clutch it will allow the head pressure get too high before it engages fully.

[@tuckerjl]

Let's see the 72 Mach 1!!!!!

[@AutoRestoMod]

It's coming we have an episode scheduled for February where we get it running.

[@SimonTekConley]

Multiple blade, who makes a 1 blade fan?

[@barryhebert5839]

An I always thought the flex/fix was best cause fans always turning long as the engine is running no matter what even though they are loud

[@AutoRestoMod]

I can appreciate that.

[@michaelakers8698]

18 wheelers have air clutches on their fan ran through a temp actuated air valve it's nothing like the clutch fan on a car or pickup

[@AutoRestoMod]

True.

[@SimonTekConley]

So you an old school fix fan on an LS. Got it.

[@scottdore132]

Engine masters on motor trend did an episode on fans, the fixed fan cost 30hp!!! clutch fan 15hp Electric fan is best for horse power.... So the question becomes What is the best fan for my application..... My vote is electric fan... or clutch fan depending on price and application

[@AutoRestoMod]

Yep. We said as much...and spent less money. LOL

[@Thirdgen83]

Still running my 46 year-old factory flex-fan...

[@AutoRestoMod]

Me too. On the '72 Mach 1. Nothing wrong with a flex fan, if that is what you want to use.

[@SuperDirtyred1]

Dad must not be a " Fan " of Children. lol

[@classicstangbrn8964]

Oooh the first to comment, great show, if you use a lock washer you don't have to nick it.

[@AutoRestoMod]

Cam and I discussed that. With that gap, the locks, at least with my level of luck, will ALWAYS fall into the gap. And if I had done flat washers and locks we would have been getting close to the 3/4 bolts being to short and the one inch bolts too long. I should have explained the method to my madness there.

[@KeepingUpWithTomF]

Good video, but Stop interrupting in the middle of his statements!

[@AutoRestoMod]

Lol, never noticed that. But his info is better than mine. We have worked together so long that is a normal speech pattern for Cam and I.

[@KeepingUpWithTomF]

Well that’s understandable Lol🤜🏾🤛🏾

[@earleclemans4836]

Electric probably pulls the same power through the alternator

[@AutoRestoMod]

As?

[@earleclemans4836]

@@AutoRestoMod as stock fan

[@TOMVUTHEPIMP]

You guys are whining way too much about the flex. The loss is not that bad, and its way less troublesome than an electric.

[@1997LT1Camaro]

Engine masters saw a 30hp loss on the dyno vs electric.

[@AutoRestoMod]

Ok. Is that for a flex or clutch? Because the Clutch freewheels under load.

[@derekdeckens2559]

This was a fixed fan not a clutch fan right?

[@1997LT1Camaro]

@@derekdeckens2559 Yeah fixed. Clutch fan was down 14hp. Im running a clutch fan on my challenger , but don’t want to jack with the appearance too much. Engine masters episode season 2 episode 20 is the one you should watch.

[@abkgang21]

Sounds like no to flex fans🤔

[@AutoRestoMod]

Yes. NO.

[@elcaminodraco]

Nothing wrong with Flex fans unless they are made of plastic IMO

[@AutoRestoMod]

Okeedokee

[@elcaminodraco]

Or on the drag strip.

[@derJackistweg]

It is way more than 5 HP that a Fan draws! Depending on where you are with your setup - it is MORE expensive to get 10 HP from anything different. I know of someone who took measurements from a Unimog U 1300. 5.6l N/A Diesel. That took 7,5 HP. NOTE: That engine just turns 3500 RPM. With a higher RPM it draws more power. There are people spending hundreds of € for a better intake, this is an easy and cheap version to tune your engine.

[@5355corvetteguy]

Get to the point!

[@looseele]

I'd really like to watch this but I cannot watch you guys constantly finishing each others sentences

[@AutoRestoMod]

HAHAHAHAHAHA, Welp. you are the first one to say THAT. I've been accused of wearing a hair piece, not being funny, called stupid the list is long and varied, but I have never had someone stop watching because we finish each others sentences at times.

[@yeboscrebo4451]

Who cares

[@thomasmacy3146]

Painful

[@AutoRestoMod]

What is painful is kidney stones.

[@ajw6715]

Gain hp with electric fans.

[@AutoRestoMod]

Clutch too.

[@ajw6715]

@@AutoRestoMod I seen a test done on a dyno with a flex fan a clutch fan and an electric fan and with the electric fan engine made 5 hp more then the others.

[@rossdean1997]

What a waste of time.

[@AutoRestoMod]

Glad you spent your time.

[@thinkingmonk9676]

@@AutoRestoMod you are a gentleman.

[@SimonTekConley]

"We're in a place what you'd call a geographic oddity, we're 2.5 hours from everywhere. " you're 15 mins from NSA, you're not that far away from things.