Fan Blade Failure

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 11"><meta name="Originator" content="Microsoft Word 11"><link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CFred_Moe%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <wunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> I inspect my ’39 Ford top to bottom prior to using it each spring, but on this I missed looking close enough and seeing the stress cracks. It is an older fan attached to a small block Chevy and is more than 10 years old. It never occurred to me that it would fail the way it did. Fortunately I was at an idle at a stop sigh when I heard a noise like my fender scraping against a curb, the blade had let go! Only had minor damage to the radiator fins but it could have been worse, way worse. Found 2 more stress cracks on other blades after I removed it which could have caused major damage had they come apart when I was cruising the expressways.
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Bottom line, inspect your fans a little closer, especially the older ones. I dodged a bullet on this one!

 

I hate flex fans...for that reason. You are the third person i've heard that happening to. One i know of went through the hood when his let go..
Not good at all!!

 

All those riveted stainless type fans are EVIL. And they are just solidly mounted fans, great power wasters even with the flexing. Replace with a temp sensitive clutch fan from an OEM installation if there's room, a '60's steel fan if space is limited.

 

You got lucky. When they come apart at speed they will go through body parts.

 

"When they come apart at speed they will go through body parts."
Yours or the car's, no problem.

 

i've taken 3 of those off cars, either mine or friends. i guess it is a good thing to listen to the old man.

 

flex fans are junk i had one put a hole in my 70 chevelle cal.hood
never agan will i use one.

 

I had an old Jeep with a clutch fan that let go while I was driving 65 mph. It missed all the important parts of the engine ie... fan belt, radiator and radiator hoses, but it hit the hood so hard it punctured a hole through the top about the size of a silver dollar. Good thing it was just an old Jeep.

 

Yeah as I'm sure this cat will agree with the fact fan blades suck when they spew a blade !!! >>>>.

 

Several years ago a local hot rodder was tuning on his 55 chevy and reved the idle speed up and the fan blades let go,,sadly he died from the head injury,,,

They are not safe! HRP

 

I was reving a FE engine in a early 70's Ford dump truck,setting the carb governor.All of a sudden a loud noise.One of then big truck type fan blades let go,went straight up missing the opened hood and through the steel roof of the garage.
Original type fans can fail also,especially old ones.

 

I thought a bomb went off when my 4 blade stock fan decided to become a 3 blade while hauling ass on the freeway . Better then than with my head and arms under the hood though !

 

Man...now a problem with THOSE style fans I didn't expect.
Something else to watch out for!

Theres a guy up here who, years ago, had to have what was left of his ear reattached and his cheek sewed up when a NEW Ford lost a blade as he was showing the Mechanic at the dealership around what RPM the mystery noise showed up!
The guy has lived well on the settlement Ford gave him for his troubles...but what a way to get rich...

A friend had a fan let go on his S10 Blazer...it took the waterpump completely off the engine and thru the rad! Just left the two pieces of the pump bolted to the block. We think the fan was damaged during the installation of the replacement engine though...not wear and tear.

 

wow thanks for the info, that is the same fan I was going to run on my T. Who knows what heartacke you saved me.

 

I had one of those big heavy duty steel fans let go on the way to Paso one morning right as I hit the on-ramp a few miles away from Spring Street - early, early a.m. and sleepy, then WHAM!. Thought the engine had blown up it was so loud. Shot the blade right through the hood (Nice way to start the show at Paso with a big jaggy hole in the hood).

So...it is not just the flex fans to look out for.

Mine was caused by a cheesy China chrome pully that was out-of-true and wobbled just enough to fatigue the blades, so have a look while you are under there and make sure your pully's run true.

 

damn, lots of fans fallin apart lately. must be a fan gremlin gettin addresses from the hamb!

 

I'm using one of those plastic fans with a lot of pitch to it, if anyone has seen a failure with that style I'd like to hear from them! Thanks Fat Fndr for bringing this one up!

 

Yup, always worth checking closely. Dont ask

 

Just keep your head to the side of the path of the blades when you do so.

 

Hadn't heard of the stock fans doing this also..THANKS for the heads up!

 

Got one of those flex fans on Henrietta the '38 Ford pickup, will be taking it off and replacing with a stock Chevy fan. I knew a guy here years ago who drove a blue and white '55 Ford Fairlane Club Coupe with a big ugly gash in the hood where a fan blade on the stock fan came off and went through the hood.

 

My father worked in Continental Motors test house and when I was old enough (early 50's) to be around cars he ALWAYS preached DO NOT stand in line with a fan especially when revving it up. He had seen enough of them let go during testing that it made a lasting impression on him which he conveyed to me. To this day you won't find me leaning over the radiator, nor on the side directly in line with the fan to rev the motor.

 

Since mechanical fans have been used on engines there have been failures and guys who've stuck their fingers in them and worse, like neckties and shirtsleeves. Like any rotating machinery, it is always best not to wear stuff that can be caught and bring your body parts up close and personal with gears, blades and small spaces.
Even the plastic bladed fans drop or pitch a blade now and then, usually with less damage than a steel or aluminum one but damage nonetheless.

I guess the number one rule would be never install a fan you haven't carefully inspected and after you do install it check the rotation at idle for true turning and no wobble. Any deviation from the norm would be good reason to scrap it. Don't sell it at a swap meet, hammer it unusable and save someone else's face or hand or hood or radiator.

And, never, ever, straighten a bent fan and reinstall it on your engine, just askin' for trouble then.

It isn't the most common problem with cars but when you're talking about parts that are often 50-60-70 years old caution should be the rule.

 

I realize this may be overkill, but it was something that came to mind when i read the stock fans can do this.
It may not be a bad idea to have the fan magnafluxed to check for cracks around the mounting points IF you are unsure, especially vintage one's.
Like i said, probably overkill..but....

 

I had one explode. just got done setting the timing rpm was at 3600. Put the hood on, went to the starting line, launched the car shifted the glide in to high and BANG.
Took out a very expensive aluminum water pump and rad, custom made alt. mount my hood and one side of my aluminum inner fender panel. Mine was about 3 weeks old. Dumb on my part to use one and a lesson I will never forget. User beware.

 

You could use an electric fan...but they're not traditional. Better to put a blade through the hood or your head.

 

Now listen here buddy....If you want to take my TRADITIONAL fan, you'll have to pull it outta my cold, dead....head?

OK...that didn't really come out right...