96 E300D W210, DIY engine fan clutch replace. How hard is it?
 

96 E300D W210,

DIY engine fan clutch replace. How hard is it?

I know this is a bit of a bozo question, but is this a relatively easy job?

Well, I suppose this depends on what vehicle you own.

Doi.
I added it to the initial post

96 E300D W210,

Not that bad, remove upper radit or brace to give you a little more room.

Do I need any special tools?
I saw one pic with an o-ring puller

I use a cut off Allen wrench.

Is it just undo the bolt in the middle to remove the entire fan assembly. Then undo the screws that hold the clutch to the fan?

Yes and as tjts1 said, use a cut down/modified allen wrench.

What prevents the entire fan from rotating when force is applied to the 8 mm Allen Head bolt that secures the fan in place?

See this for the W124, which I think is similar/same to yours for this job:
https://m.youtube.com/watch?v=UwPf_sSTL7s

I'm trying to remember.but it seems I have taken a good, used piece of serpentine belt, wrapped it around the pully and locked it down with a pair of vice grips to secure the fan.

Speed. The bolt isn't in there that right, if shouldn't be. Push down on it hard once and it lets go. After that it just spins out.

I hate that design, it makes accessing anything on the front of the engine a PITA. I ditched the fan clutch, it doesn't do much good on this engine anyway.

How did you ditch the fan clutch?
Doesn't the clutch just keep the fan from self destructing if
obstructed and or avoid severely mangling fingers.
I read one guy said he abandoned this fan entirely and replaced with an electric fan.

I got rid of the whole fan and clutch. The electric fans are more than enough for the non turbo diesel.

Assuming the diesel is like a m103 or m104 its not bad at all. You need to get the plastic fan shroud out of the way and often the radiator too if its been on there a while and you really need to force it. If you want to leave the rad in you may need to cut down a 10mm allen wrench.

The belt usually provides enough grip to keep the pulley from spinning. If its not enough use an old belt and wrap it around the fan pulley and a few others. Then bunch up some extra and run it over itself to lock everything up. This should not the first attempt but as a last resort on a stuck bolt its better than rounding off the 10mm hex bolts on the back of the pulley.

Do you mean the stock electric fan in front?

My electric fan threw the tiny belt that turns the passenger side of the two fans.
The one on the right has the motor. The one on the left has a tiny belt.
Looks like that part is available.
I think I will just remove the fan.

Grrr.. This seems like a knuckle shredder.

In case you are still wondering, there is a hole on the back of the water pump flange that can be aligned with the Ridge on the top of the water pump.
Align the hole just to the driver side of that Ridge and place the tool (there is actually a tool made for this; I used another tool and also think one could be made. Once you have it aligned you will see how it works and what will work to hold it in place.)
When you turn the bolt the tool that you use will act as a stop on that ridge.
When you put it back together just align the hole on the passenger side and it locks it as you tighten the bolt.
If I was home I would get pictures of it for you but I just did this job about 4 times on my 99 (don't ask!).
As previously posted, unbolt the 4 tens holding the upper rad support as this allows just enough room b/t the rad and clutch fan bolt

Thanks hogweed.
I'm gonna try to hold the belt the stupid first and then I will take a look at your suggestion.
BUt I will loosen the rad support.

Cutting the allen wrench was the hardest part.

I didnt even have to pull the rad support. But it looks like I have to pull it to replace the belt on my electric fan... its missing.

I didn't block off the belt. Just used a 2 foot cheater bar and braced my right hand against the power steering pulley and gave it a medium yank to break it loose.

pizza box helps here. cut it open and slide it in.

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cut off allen wrench?
 

Okay Ive seen this suggested in various situation and Ive tried to cut an allen wrench which is tool steel, like cutting...tool steel. Tempered, hardened and no saw will touch it, so how, really, do you cut an allen wrench? grinder perhaps? Space alien tech or dental drills? Lasers? Plasma torch?

Dremel with a cutoff wheel. Wear eye protection, use a vice.

I used a side grinder.

I used a masonry cutting wheel on a beat up old ryobi saw.

But a grinding wheel from grampas work shop would work.

If you don't have either of these get a grinding wheel for your power drill from a hardware store.

If you can't do that you could put it in a drill as a bit and spin it against an old school metal file and

If you cant do that rub it against a rock for a few hours.