What could make 2 blades break off a fan?

Zachary Hoyt · Jul 11, 2013

I thought I had seen it all but now I am completely stumped.
Was out mowing hay with the Massey 35 which is my backup
tractor since the Farmall had a problem this morning. 35 has
been overheating, gradually worse over the years. I just try to
clean the radiator fins and carry on, and when the temp gauge
gets hot I wait till it cools down. Tonight I heard a sound and
when I shut off the tractor to look I saw that two of the fan
blades had broken off right by where they are riveted to the hub
on the water pump. They are opposite blades on a 4 blade fan,
what would be 3 and 9 oclock. The other two are still there and
look fine, there is no sign of damage to the tips like they had hit
anything. I was able to find one of the broken off blades and it
looks like it was metal fatigued or something. One blade made a
hole in the radiator near the top. I have never seen this happen
before, if anyone can shed any light on the problem I would
appreciate it.
Zach

Zachary Hoyt · Jul 11, 2013

Here are pictures of the blade I found.
Zach

Royse · Jul 11, 2013

Original fan or aftermarket?
Either way I guess it could be metal fatigue.
Maybe they were flexing when running causing it
not to move air well enough to cool the engine.
New fan may fix both problems if so!

Zachary Hoyt · Jul 11, 2013

Looks aftermarket to me, will know more once I get it off the
tractor.
Zach

36 Coupe · Jul 11, 2013

This happens a lot.My sons chevy pickup had a fan let go.It was the 2 piece type with thin stainless blades riveted to a steel hub.This fan could have been badly bent and attempts to straighten it cracked the steel.My sons fan cracked near rivet holes.This points out the danger of revving an engine while standing in line with the fan blades.A fan could be out of balance and vibrate at high speeds.

Dean · Jul 11, 2013

Metal fatigue.

Not uncommon, especially for a 60 year old machine.

Usually caused by unbalance.

Dean

JMOR · Jul 11, 2013

(quoted from post at 18:59:28 07/11/13) I thought I had seen it all but now I am completely stumped.
Was out mowing hay with the Massey 35 which is my backup
tractor since the Farmall had a problem this morning. 35 has
been overheating, gradually worse over the years. I just try to
clean the radiator fins and carry on, and when the temp gauge
gets hot I wait till it cools down. Tonight I heard a sound and
when I shut off the tractor to look I saw that two of the fan
blades had broken off right by where they are riveted to the hub
on the water pump. They are opposite blades on a 4 blade fan,
what would be 3 and 9 oclock. The other two are still there and
look fine, there is no sign of damage to the tips like they had hit
anything. I was able to find one of the broken off blades and it
looks like it was metal fatigued or something. One blade made a
hole in the radiator near the top. I have never seen this happen
before, if anyone can shed any light on the problem I would
appreciate it.
Zach

just mark it up to metal fatigue. Worst I ever saw was one of an inline 6 truck engine & it cut completely through the hood of the truck! Sure makes me think of my position relative to fan when working & revving an engine!

Anonymous-0 · Jul 11, 2013

Shiny spot looks like it's been flexing for a long time. If you want to fix it cheap, measure radiator, and go to a junkyard, and pick up an electric fan that fits the radiator, and blows the right way.

Zachary Hoyt · Jul 11, 2013

Either I am lucky or these are a lot more common than I thought. I went in the shed to look at the fans I have and the first one I picked up fits perfectly, same diameter, same bolt pattern and center hole. Only difference is the blades are a bit narrower. This came off an Allis B that I parted out, so it was made over 20 years earlier than the Massey which is a '63. Now I need to repair the three damaged tubes on the radiator and put it back together and maybe I can get back to mowing tomorrow. It sounds like fan breakage is a fairly common thing, I guess I just don't get out enough to hear about things. Thank you all very much for your help.
Zach

El Toro · Jul 11, 2013

Broke probably from metal fatigue. Happens to airplanes sometimes from takeoff and landing. Hal

Adirondack case guy · Jul 11, 2013

Must be the day for fans to go bad. Bro out in Wyo. just posted about his Case 955 swather sheading the fan hub off the water pump, and taking out the radiator, over on the case forum.
Loren, the Acg.

Unruh · Jul 11, 2013

Just wondering, You say you clean the fins and carry on....Is an uneven airflow through those areas have anything with flexing the blades? Just wondering.

Whichester1 · Jul 11, 2013

Could be most anything, maybe somebody tried to rotate the engine using the fan blades.

It also could be as simple as somebody blocking off part of the radiator during cold weather. The correct way is to block off all sides equally.

Check the bearings too.

Your replacement fan does look stronger.

ss55 · Jul 11, 2013

As others have said: imbalance, uneven air flow, and vibrations all contribute to metal fatigue.

I cringe a little when ever someone suggests pulling on a fan blade to turn an engine over. I've done it too, but not anymore. That has to be way more force and stress than most fans were built for. If the fan blade bends it has been over-stressed and now the fan assembly is out of balance.

Tony in Mass. · Jul 11, 2013

Let me say an unpopular thing.. which I do a lot on here. While you are all appart, take off the thermostat housing, take out the thermostat...AND LEAVE IT OUT! There, now people can pick on me for being ignorant.
But you have a constantly hot engine, and you are maintaining the radiator, which now is a good time to flush out, even with just a garden hose, and give that dodgy AC fan a milk run with fingers, not a powered spinning fanbelt, cause it could have more dimensions off than just the pitch. And the metal fatigue of that thing might be only hours behind the 35's original. Good luck and be careful.

buickanddeere · Jul 11, 2013

You answered your own question. The partly plugged rad does not allow equal airflow. The blades flex as they pickup greater and lesser amount of air .
Rad requires 100% full access and remove all the oily mud. Or blade failure will occur again.
Seen pictures of a natural gas fueled gas turbine at an electrical generating plant. Broke a first stage compressor blade due to a paper towel roll. The roll of towel was blocking flow between two stationary inlet stator blades.

Anonymous-0 · Jul 11, 2013

been a strange day ,,.fan blades breakin off proves it ,,I hadto file on a screwdriver in order to change points so I could start the loader tractor to make repairs to the haybine lift struts .just finished at dark ,,I had hoped to be cutting hay around noon today . then the house water pump lost prime and had to go in and spank its az and get it going again . have not read about cnts breakdown yet ,,. but his problem and this reminds me of the time the waterpump housing broke on massey 300 slant 6 combine ,, belt was not overtite ,,no forighn trash in the system,,cjean braek on a hot day ,, never did figure it out ,, now I wonder wherethe hale the 1 inch soket and ratchet wemt to when I was worrkin on the haybine out in the back yard

Case Nutty 1660 · Jul 11, 2013

as bad as it was it could have been much worse this rad is non repairable only a new core will do it it has three deep cuts this one as Bro Loren said shed the hub from the pump shaft from the looks of it it seemed to be moving on the shaft before coming off the pump was a reman and was in good shape other than the hub must have been to loose

37chief · Jul 11, 2013

I had a fan blade brake on a chevy motor, and go through the hood, never to be found. I will never stand in line with a fan on a running motor after that. Stan

Dean · Jul 11, 2013

Bingo.

About 30 or 40 years ago, a guy was found dead beside his car (hood open) on I-75 near Dayton, OH with a fan blade through his heart.

The dangerous scenario is loss of one blade causing a serious imbalance. The driver then opens the hood to see what is wrong, revs the engine, and another blade that is also fatigued breaks off. This guy just happened to be in the way.

Dean

rustred · Jul 12, 2013

ever see when somebody puts cardboard in front of rad to warm up in winter? well that is a good example of fan stress, by only having partly covered rad. when doing this you are to have a round hole cut in cardboard and have the hole centered in front of fan. this way you get even airflow through fan and does not create a wobble on brgs. also.

D beatty · Jul 12, 2013

It could be just from old age and metal fatigue.

Bob · Jul 12, 2013

I'm with you, D beatty, on this. The newest "35" was "hatched" just short of 60 years ago, and it would be ALMOST reasonable to conclude there is a little bit of an "age factor" involved with ANYTHING that old that breaks!

WHAT do you suppose any of the little tractors on the market now, that are more plastic than steel/iron/ will be like when they turn 50 or 60 years old?

Craig45 · Jul 12, 2013

Never thought much about a fan braking like that before. I'am going to look at my tractor fans and make sure there are no cracks.

DaninKansas · Jul 12, 2013

One blade broke off and hit the other blade while falling/bouncing out of the engine causing it to break off too. Combined with 60 year old metal it's probably just luck they didn't take all the blades out at once. Since it damaged your radiator I'd look at this as the chance to fix your overheating problem.

fixerupper · Jul 12, 2013

I had one break off of a combine engine. There was no damage, no nicks, marks, scratches, just a missing blade. Had a heck of a time trying to find the source of that vibration. Jim

David G · Jul 12, 2013

Why in the world would you take out the thermostat?

KF · Jul 12, 2013

I have a TE-20 that I restored that had the riveted fan blade like you have. Likewise, there were cracks in the blade between the rivets. So I got a blade from a TO-20 and it was like the spare one that you have in that the blades are not riveted. So in my mind the riveted blades do not stand up to vibration and flexing over a long period of time and are prone to failure. From my experience I would never put another one back on.

dpendzic · Jul 12, 2013

every metal device has its own resonate frequency where the out put is 2 times or more than the energy put in. This output energy is derived from the breakdown of the metal molecules and eventually a crack develops.
Even when i was designing plate girders for bridges every welded connection was designed at a reduced stress level due to the girder being stressed every time a truck went over it. A typical urban bridge was designed for 500,000 cycles. Rural would be less and metropolitan for more.

Janicholson · Jul 12, 2013

Don"t remove a thermostat. They keep the engine at a temperature that allows good combustion with no detonation. Good fuel vaporization. Proper oil viscosity. Reduced condensation in every part.
and higher efficiency. There are no good reasons to run any engine without its designed in Thermostat. Test it and replace or reinstall. Jim

Dick W. · Jul 12, 2013

I would try really hard to find the other blade before a rear tractor tire finds it!

cshess · Jul 13, 2013

Those blades are hard tempered metal. I bet more than one time in there life someone might have tried to turn engine by grabing fan.Not a good idea .

What could make 2 blades break off a fan?

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