Radiator, meet your mean spirited cousin Flex Fan

t-west

t-west

Well-known member
Hi all,

So what would make my flex fan lurch forward and bite my radiator? When I pulled over after the grinding sound and smell of radiator fluid, I noticed the forward corner of one of the blades had been bent back as if it had caught on the radiator itself.

I have a three row radiator and a flex fan, the kind that gets narrower as your engine revs, both about 6 mo. old.

Motor mounts look okay, as does the new water pump I installed. Radiator didn't shake loose or anything. This all happened, incidentally, while I was accelerating hard in second gear.

Here's a pic:

rad.jpg


Clearance is tight, just shy of 1/2 inch.

clearance.jpg


I'm headed to buy a new radiator and a "thinner" fan tomorrow or Saturday and want to make sure I've not done something worse than measured too poorly.

Thanks in advance for any potential explanation for why this has happened.

--tom
 
I know you said it was a new water pump, but my first thought is to check for wobble after loosening belt.

Also possible(?), driveline too long, not enough "slip space" on the yoke. Rear end torques up, pushes driveshaft forward, which bottoms out in tranny and pushes everything forward.
 
I have a nylon fan, or some kinda composite, and the blades on it push forward at high rpms. At redline it gets really close to the radiator. This might be what happened.
 
Honestly, my fan is secure and motor mounts are fine but the engine still torques pretty good. I just made sure I had a good amount a clearance by using the shortest fan spacer I could find.

Sorry, man. I would have been in the same boat if I hadn't read a post about this the exact same week I installed my 3-row.
 
HI
Looking at the pic it looks like its cut more at the top of the rad.. I'd check the tranny mounts. like the other guy said the tranny may have picked up and so the top of the fan hit the rad.
tim
 
The blades do flex forward when you rev it, a combination of factors previously mentioned is what did it.
 
8) your fan clearance is tight to begin with. just because the motor mounts look good visually doesnt meant they are good. that also includes the trans mount as well. replace the mounts, check you current clearance between the fan and the belts as it looks like you can use a shorter fan spacer. one othe roption is to replace the mechanical fan with an electric fan.
 
Thanks to everyone for the info. I'm off to Mustangs Plus today to pick up motor mounts, radiator, and different fan. I'm leaving the trannie mount as it was replaced this summer when the C$ was rebuilt. While I'm under there, I'll look for signs of a cracked frame :shock: .

Any tips on lifting the engine enough to replace the motor mounts without bending the pan? A 2X4 to distribute the weight?

I'll let you know what I find.

thanks,
--tom
 
I just put a scrap piece of plywood between the jack and pan when I changed mine, worked fine.
The only problem I had when changing mounts was the ground I was on was not as level as I thought, when I started to lift the engine it started to tip to the side :shock: Live and learn I guess.
 
I've replaced it all, the motor mounts, fan (with a six blade, non-flex style), radiator (same 3 row as before), only this time was able to go with a smaller fan spacer, a 1/2 inch (instead of the stock 2").

I'm really concerned that this will happen again until I know why it likely happened the first time. I had expected my motor mounts to unbolt in pieces, but they didn't. How do I know that these are bad?

IMG_3625.jpg

IMG_3623.jpg

IMG_3627.jpg


Of note, on the new ones, the left and right are different in the following way -- the "curve" of the metal part over the rubber part goes in different directions. In these, it's the same. Did I have two motor mounts of the same side installed? If so, would that have caused the play?

Also, trans mount was new this summer when the C4 was built. No visible cracks in the frame.

thanks,
--tom
 
It doesn't look bad to me. I'm not sure if there is a left and right side. I replaced mine 4 or 5 years ago and can't remember. I think you'll be ok with the new fan spacer. Good luck.

kevin
 
wallaka":2cz7dq7v said:
It doesn't look bad to me. I'm not sure if there is a left and right side. I replaced mine 4 or 5 years ago and can't remember. I think you'll be ok with the new fan spacer. Good luck.

kevin
Click to expand...

i agree, but take a magnifying glass and look the rubber over carefully for any cracks. put the bolt in a vice, and bend the rubber around while looking.
 
I didn't have to look hard at mine... Whenever I hit the gas, the gearshifter moved 3 or 4 inches back and forth :shock: :shock: I was a little concerned.
 
This first happened when I tried to pass someone, RPM's up in second gear. Because my original clearance was 1/2" (or under!), I'm guessing it moved just enough to catch the leading edge of the flex fan, which then bent backward, catching much more.

I'll drive it easy until I'm certain. Thanks to all for your help.

--tom
 
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