[E46] Do I need to replace my fan clutch?

[Joel61 9]

Hi guys

So I recently picked up another E46 320I and I am having a problem.

It seems the clutch fan is always engaged. 
When the car is off and cold I can't manually spin it, where on my other E46 it can spin freely.
When I start the car up, it sounds like a bus, with the fan spinning really fast and pushing out a lot of air which I can feel when I put my hand over it. Where with my other E46 it start spinning slowly like it should when I first start the car up.
When I let the car warm up it still seems to be spinning very fast and does not slow down from when I initially started the car and, when I give it some gas it sounds like a bus taking off.

Now my question is, is the fan clutch buggered and should I replace it, or would it be something like the temperature gauge that is reading wrong causing it to stay engaged?

Thanks

P.S If you need anymore information or a video, please let me know

[jonoe30 53]

Sounds exactly like a broken fan clutch as its moving in time with engine revs. The clutch allows the fan to spin freely when disengaged until the clutch expands thermally and locks the shaft to the casing, rotating the fan in time with the engine. There's nothing electronic involved it's operation.

If you're replacing it yourself remember it's reverse threaded and you'll need a thin wrench to get at it. When you pull it out you'll need to carefully lift the fan and shroud out at the same time. There's lots of how-to's on youtube you can watch.

[Joel61 9]

Just now, jonoe30 said:

Sounds exactly like a broken fan clutch as its moving in time with engine revs. The clutch allows the fan to spin freely when disengaged until the clutch expands thermally and locks the shaft to the casing, rotating the fan in time with the engine. There's nothing electronic involved it's operation.

If you're replacing it yourself remember it's reverse threaded and you'll need a thin wrench to get at it. When you pull it out you'll need to carefully lift the fan and shroud out at the same time. There's lots of how-to's on youtube you can watch.

Awesome! Thanks so much for clarifying this for me. Is there anything I need to look out for when buying a new fan clutch? 

[jonoe30 53]

Not particularly, they have been standard fitment on BMW's for many years and are a simple design so they are a known quantity, just look up the last 7 digits of your VIN on realoem.com to get the exact part number... The OEM clutches are usually made by BEHR (I'm unsure of the exact OEM brand for the M52/54 engine). I would check out prices locally through Milland if you need it in a hurry, or you could buy through FCP Euro from the US and shipping is usually less than a week (I've had parts arrive in 3 days using their standard UPS service, as long as it doesn't get stuck in customs).

[zero 1162]

I would do the fan delete mod.

 

The clutch fans are known to explode and take half the cooling system with them. Some even put dents in the bonnet.

If you are spending money on a clutch fan, better to spend the same money on the fan delete mod.

Engine will be quieter, rev smoother and use less fuel.

[Joel61 9]

29 minutes ago, zero said:

I would do the fan delete mod.

 

The clutch fans are known to explode and take half the cooling system with them. Some even put dents in the bonnet.

If you are spending money on a clutch fan, better to spend the same money on the fan delete mod.

Engine will be quieter, rev smoother and use less fuel.

So you are just saying I can remove the fan and it would still run fine with the auxiliary fan? Do you have any more information about this?

[zero 1162]

Google 'e46 fan delete mod' - its a very common mod.

E46's came from the factory with either the viscous fan and auxilary fan, or with the more powerful electric fan.

 

You remove the viscous fan and the auxilary fan.

Then you put in the electric fan - it bolts straight up to the factory mounts and the factory wiring plug.

I've done it on both my e46's with great results. 

[zero 1162]

Here is a good thread explaining it;

http://forum.e46fanatics.com/showthread.php?t=884299

[jonoe30 53]

1 hour ago, zero said:

I would do the fan delete mod.

 

The clutch fans are known to explode and take half the cooling system with them. Some even put dents in the bonnet.

If you are spending money on a clutch fan, better to spend the same money on the fan delete mod.

Engine will be quieter, rev smoother and use less fuel.

Nice Looks like a good factory solution if it can be done for similar money!

As zero has noted re the fan exploding; don't drive it while the clutch is locked up.

Edited October 3, 2016 by jonoe30

[hqstu 780]

Just a bit more to this, a new fan clutch will initially spin up and pull air when first started cold ( a bit of wind roar), but will then disengage after about a minute or so, until heat from the radiator re-engages it for actual cooling purposes.  I've just replaced mine, easy job, get right tools, careful with fan shroud etc as you lift it up to remove.  Handy at same time to replace fan itself, and if really keen do water pump and thermostat whilst you are in there (taking shroud out completely).  Easy as..

I personally can't see the point of (mechanical) fan delete with a clutch and fan in good operating condition...

[allan 295]

Have a look on e-bay the electric replacement fan units seem to sell for around 100 to110 then you have freight to pay. The fan couplings  range from 80 up to 300 for a gen BMW plus freight again. Both systems have their pro's and con's up to the individual to choose.

http://www.ebay.com/itm/New-Cooling-Fan-Assembly-Fits-99-06-BMW-E46-3-series-325-330-17117561757-/271957793065?fits=Make%3ABMW|Model%3A325i&hash=item3f51f29929:g:JNUAAOSwgApXA1dP&vxp=mtr

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2014.cgi?command=show_part_page&please_wait=N1&make=BMW&model=0216&section=WATRAD&page=5&bookmark=12&part_number=11-52-7-505-302-M6

Edited October 5, 2016 by allan

[hqstu 780]

It's interesting that every BMW I've owned has had a failed fan clutch when purchased.  How many are running around during summer with only the air con electric fan providing any air during hot and heavy traffic?  BMW had them designed in for a reason...

[Joel61 9]

Hi guys, just an update. I replaced it and it was fine and fixed. 

Also @hqstu I have never had to replace the fan clutch on my other e46 (2001)...come to think of it, I don't think I have ever had any problems with it 

Edited December 28, 2016 by Joel61

[jonoe30 53]

3 hours ago, hqstu said:

It's interesting that every BMW I've owned has had a failed fan clutch when purchased.  How many are running around during summer with only the air con electric fan providing any air during hot and heavy traffic?  BMW had them designed in for a reason...

Interesting... the fan clutch is designed so that if it fails it will be with the clutch engaged so they should be driving around making a lot of noise!

[hqstu 780]

1 hour ago, jonoe30 said:

Interesting... the fan clutch is designed so that if it fails it will be with the clutch engaged so they should be driving around making a lot of noise!

Hmm, well all mine have just been free wheeling at any temp, cold or hot, and can stop fan with hand easily anytime.  I suspect a lot of owners have never noticed, all present company excluded of course   When cold a fan can move but there is resistance and stops quick.  If dodgy then it will spin easily forward or backwards.  Unless as you say it's gone the other way and locked up completely.

[Allanw 1071]

That newspaper test people say to use is a crock too.

 

it ONLY works if the coolant in the radiator is hot enough AND it's transferring enough of that heat into the bimetal mechanism on the fan clutch to trip it. It's pretty un-scientific.

If the gauge is pegged, and the fan is still freewheeling, it's probably faulty

 

Some have been known to leak the fluid out, then they don't work very well, and can seize - locked up.

Some wear out the friction/bimetal mechanism, so DON'T lock up, when they should.