So I thought I had a problem with my alternator. Red light is on and alt not charging. Found out that my fan is not turning. Belt is on and engine runs fine. Is it time to drop the engine? Is it time to get another engine?

Thanks in advance.

It’s connected to the crankshaft on a hub with a keyway and a bolt. There’s three bolts holding it onto the hub. I would start checking there first.

Check the belt tension /condition first before jumping ahead,your fan will always drive but your altenator needs the above to work right,make sure you buy the currect belt,sorry but have forgotten ,its more about the width which works right with the 914 altenator drive pulley.

If the fan isn't spinning you have a serious hub issue.
It could be checked in car, but it's likely going to be coming out. The fan could lost it's bolts and sheared the pin, or a DAPO could have left the hub key out.
Or the crank nose broke off, never heard of it happening in a car, but it has happened to T4 aircraft guys.

The key could have been improperly installed and pushed/slipped into the engine when the fan hub was installed.
It would've had to been a big jolt to shear the hub key.

I can't imagine the engine running, and the impeller not turning without making a serious noise

Thank you everyone for the helpful advice. The belt is the right size and properly installed. The issue started after I got back from our family vacation a few months ago. I asked a friend to stop by our house on weekends and water the plants and warm up the cars so battery won’t go bad. He don’t recall any loud noise. I’ll get the engine out one of this weekends and

Can use a cell phone and take a picture of the center of the fan? Here’s a few shots of the crank with the hub and keyway. You should be able to reach down inside the fan to feel if the three bolts are still in place. There’s also a shear pin on the hub.

Buy a couple of battery tender/chargers.

Crank, keyway and fan.

Whoa, subscribing for this one...

Click to view attachment

Tried to remove the bolts but it wasn’t cooperating. I have to drop the engine. The fan is pretty easy to rotate with hand. The fan from my spare engine is not as easy to rotate.

Ok so the three bolts are in place you definitely need to drop the engine to see what’s going on. The center cone pops off and the bolt that holds the hub on is behind it.

Be forewarned, that hub held by the center bolt sometimes takes a hub puller to get it off the taper.

Might want to start by just removing the 3 bolts that hold the fan to the hub and then see what you can see.

None of this will be easy or fun to do with the engine in the car. Per your previous comment, best to drop the engine.

Definitely sounds like something with the hub/crank key is the cause, Abe.

With the right tools, you can remove the fan and inspect everything. I'd recommend getting an inspection camera, either a stand alone from Harbor Fright, or one that works with a 'schmart fone'

For those who experienced this, are we saying probably the hub between fan and crank got loose? If yes, is the fan should fall or dismantle with the crank easily?

Hope the crank is not damage and may need engine rebuilt. Borrowed picture from one of the member’s thread.

Click to view attachment

Click to view attachment

Yuck

Got the engine out yesterday. I think the woodruff key got flattened out.

That's....unusual.

But if the crank is good, an easy fix.

That’s what I am hoping

Click to view attachment

Unless I'm misunderstanding the pictures I think it wasn't flattend out, it was sheared off.

Woodrun keys are not hardended and are designed to shear.

What is really odd is that something caused it to shear. Would think it would have been something that almost instantly stopped the crank (massive backfire?) and then inertia of the far sheared. Alternatively, instant seizure of the alternator with a belt so tight that it couldn't slip?

I know it took a long time to get this far but the good news it doesn't seem to be permanent damage or something crazy like the crank nose broken off.

I'd look round just to make sure there is no other obvious root cause. Lacking that, put back together and call it a day and be glad the woodruff key served its purpose. It died so that rest of the components could live on.

Not sure crank looks a bit chewed up,the key has tipped over till it finally sheared the top off and caused the hub to spin,it will most likely be ruined also.
You could purchase another key and hub and lap it in again but you need to replace the crank seal,there will be bits of other crap in there also.
As mentioned the Woodruff key isn't hardened as with the crank nose so if a new key is loose you have issues,good luck.
Hope it works out,shame someone didn't tighten the hub centre bolt properly from the start.

Abe’s engine still runs except battery is not charging or the voltage red light was blinking and tried several items what is wrong and then Abe noticed the fan was not turning while engine runs. Hope the woodruff key is just the only damaged. Now his doing more work since engine was drop. Push rod tube seals, front crank seal and general cleaning of his engine from various oil leak.

I would say it is the taper that holds the fan hub to the crank. The woodruff key locates the position of the fan. The fan must have been a little loose and small movement back and forth eventually sheared off the key. Without a proper fitting taper on the hub and crank. This could happen again.

You are correct. Taper is what holds the parts together - not the woodruff key. Many machine tools operate and resist rotational torque only by virtue of an interference fit via taper. Examples: Morse Tapers for lathes, Jacobs tapers for drill chucks, etc.

As perviously stated by @porschetub , the best bet is to remove any burrs off the crank nose from the slippage, then use the hub along with with some very fine lapping compound to lap the two back to a tight interfernce fit. And replace the crank seal while you have easy access. Finally, use a torque wrench to reassemble. I'm always amazed by the number of folks that don't own, and/or, don't use torque wrenches. A must have item.

this reminds me of my recently acquired $20 gas powered edger. wouldn't start, weak to no spark. i found a similarly sheared key when i removed the flywheel (ignition trigger is here). i replaced it and the darn thing fired and then died. sure 'nuff, another sheared key. turned out a missing washer between the flywheel and starter clutch that held it was the reason for the looseness of fit that kept shearing the keys. i think bartlett nailed it.

Come to think of it, the fan hub was loose when i removed it. i'll make sure it have a proper fitting taper before the engine goes back in.

Thanks everyone. Stay safe.

Sung to Journey's 'Wheel in the Sky' tune ...

Ooh, the fan on my car isn't turnin'
Will it leave me stranded tomorrow?
Fan my car motor isn't turnin'