Mechanical Fan Exploded! Is another one Justified?

A few weeks ago the fan in my 530i decided to go BOOM. Luckily it was in my garage with the hood open. It destroyed the belt, WP pulley, radiator hose and radiator shroud. Surprisingly the radiator was untouched.

I know I could easily replace these parts and install another mechanical fan but is that a smart move? How can I justify installing another mechanical fan (small bomb) when they have potential to do so much damage. My fan had less than 10K on it.

I think this is the opportune to overhaul the cooling system my way. Of course this will entail a dual electric fan setup

You probably used the "MTC" brand Fan Blade.
When I overhauled my cooling system, I was trying to save a few bucks by buying MTC Fan Blade.
Luckily during a routine check, I saw the crack in the plastic at 1yr/10K mark!
I immediately went to dealer and got the BMW Fan Blade, which is supposed to last some 8-10yr/100K miles.

I dont know what brand the fan is/was. The previous owner put it in. I will double check see if I can find any brand marks on it.

Perhaps an INDY in the Mpls area did the work and would have records.

Originally Posted by [URL="http://www.bimmerfest.com/forums/member.php?u=94354"

S C H I T zo[/url];6261185]My fan had less than 10K on it

MTC perhaps?

I don't have personal experience with the exploding fan, but, from the anecdotal read, it seems the problem is most often not the fan itself.

It seems, although this isn't conclusive, that the real problem is either the viscous fan clutch or faulty motor/transmission mounts.

If that is the case, then your next mechanical fan will suffer the same fate.

However, if you want to switch to electrical operation, you'll find details here:
- Mechanical fan delete DIY fan clutch to electrical fan (1) (2) (3) (4) (5) (6) (7)

Much more likely the water pump is going out and allowed the fan to drop down and impact the radiator shroud. Its very rare the blade just decides to fly apart on its own.
When the water pump or fan clutch bearing start to fail they allow the fan to dip down and come into contact with the fan shroud and that causes it to fly apart.

Make sure to check for play in the fan clutch and water pump if you re-use them.

You should review old cooling system records (if available) and start thinking about a cooling overhaul.
I mean a COMPLETE cooling overhaul, NOT bits and pieces.
Otherwise you will learn it the hard way.

Originally Posted by bluebee

MTC perhaps?

I just checked. It is OEM with a BMW logo on one of the blades.

Originally Posted by oembimmerparts

Much more likely the water pump is going out and allowed the fan to drop down and impact the radiator shroud. Its very rare the blade just decides to fly apart on its own.
.

The water pump seems fine. No play at all. This is the water pump in question
http://www.bimmerfest.com/forums/sho...297&highlight=

Originally Posted by cn90

You should review old cooling system records (if available) and start thinking about a cooling overhaul.
I mean a COMPLETE cooling overhaul, NOT bits and pieces.
Otherwise you will learn it the hard way.

Yes I will be doing a complete overhaul. Only the fan and coolant reservoir will no longer be stock E39.


It goes without saying that the mechanical fan is good at what it does. i.e cooling the engine. However BMW chose to eliminate it in other models after the E39 such as on the E46 and E60. Im sure it was not due to inability of the mechanical fan to cool the engine. Is it perhaps due to the potential for these fans to explode? I am yet to hear of electric fan blades exploding.

Originally Posted by *****zo

...Yes I will be doing a complete overhaul. Only the fan and coolant reservoir will no longer be stock E39.


It goes without saying that the mechanical fan is good at what it does. i.e cooling the engine. However BMW chose to eliminate it in other models after the E39 such as on the E46 and E60. Im sure it was not due to inability of the mechanical fan to cool the engine. Is it perhaps due to the potential for these fans to explode? I am yet to hear of electric fan blades exploding.

Actually the Fan and Reservoir should be stock BMW parts.
Aftermarket parts are historically bad (search for horror stories).

Re deleting Fan Clutch and Fan Blade, all FWD cars such as Toyota Camry and Honda Accord etc. have no Fan Clutch. The Aux Fans in these FWD cars (one just in front of AC Condenser and another fan between the rad and engine) do the cooling jobs.
Fan Clutch is only possible on longitudinally mounted engine.

Originally Posted by oembimmerparts

When the water pump or fan clutch bearing start to fail they allow the fan to dip down and come into contact with the fan shroud and that causes it to fly apart

This (the bad waterpump cause) is new information, to me.

Since it may be new to others, I'll add this thread to the bestlinks:
- What could cause a fan blade to disintegrate (1) (2) (3) (4) (5)

Summary of reputed causes of fan disintegration:

• Bad fan itself (rare)
• Bad motor or transmission mounts
• Bad viscous fan clutch
• Bad waterpump

Originally Posted by cn90

Actually the Fan and Reservoir should be stock BMW parts.
.

No worries the Coolant reservoir will be BMW just not E39.
What I have found is that BMW has two types of reservoirs. The kind found on the regular E39 and the kind found on the E39 M5. The construction of the latter reservoir is much more robust and does not suffer from developing pinholes or blowing up for that matter. All you have to do is hold one and you can tell the difference right away. These tanks have much much thicker plastic.

This same construction is employed on the E30/Euro E36 coolant reservoir. As such, I will replace my reservoir with the E30 tank. You will only ever need one reservoir for the rest of the car's life.

When mine grenaded it was the clutch that was the cause.

zionville! I'm planning to do the zionville on my car fairly soon. Just seems like the right choice since you won't have to worry about the cooling system nearly as much afterward.

E39 clutch fan is a power robber water pump destroyer self destructive timing bomb. Glad I don't carry it with me.

Robert, electric fan is way to go

Originally Posted by bimmernut1

When mine grenaded it was the clutch that was the cause.

Haven't figured out the cause in my case.

Originally Posted by peetiewonder

zionville! I'm planning to do the zionville on my car fairly soon. Just seems like the right choice since you won't have to worry about the cooling system nearly as much afterward.

Good kit just overpriced in my opinion.

Originally Posted by 16valex

Robert, electric fan is way to go

I could not agree more. I just cannot find any reason why I would want to install another mechanical fan after personally seeing what it can do when it disintegrates.I already have a dual fan setup in the works.

I would also appreciate any comments on my statement above regarding BMW's choice to go to electric fans on the newer chassis such as E60 etc.

Drove my mom's Accord in July... it was the noisiest POS because of the damned electric fan. If I dropped below 20kph the fan would kick in louder than my E39 ever does.

BMW replaced the fan with an electric one on newer cars, but they also (i imagine) did some programming work to make it function in a non-intrusive way. Aside from blowing up sometimes, the mechanical fan is a lot less intrusive than the electric.

Originally Posted by bmw_n00b13

Drove my mom's Accord in July... it was the noisiest POS because of the damned electric fan. If I dropped below 20kph the fan would kick in louder than my E39 ever does.

Fan noise is dependent on the motor used and the how the blades are cut. My 528i has dual 13" fans that you cannot hear even when they are running at full speed. The same applies to most OEM setups.

Originally Posted by bmw_n00b13

BMW replaced the fan with an electric one on newer cars, but they also (i imagine) did some programming work to make it function in a non-intrusive way. Aside from blowing up sometimes, the mechanical fan is a lot less intrusive than the electric

wouldn't an exploding fan be considered intrusive?

*aside* from blowing up sometimes. .

One nice thing about the factory fan clutch is that: at any given moment, the fan blows some air so the Plastic components (yes there are tons of plastic parts under the hood) are somewhat cooled down a bit.

If you do a cooling overhaul every 80-90K, these parts (fan clutch, fan blade) do not have a chance to blow up.

I would also appreciate any comments on my statement above regarding BMW's choice to go to electric fans on the newer chassis such as E60 etc.

I'm sure it has something to do with it. Let just take a look at our community between Bimmerforum and and Bimmerfest, we're probably represents a small percentage of all sold E39s out there and yet there're a number of clutch fan explosions, it clearly defined high if you look at Per capita.
Considered, we're a bunch of fanatics car enthusiasts. Can you imagine the amount of fan explosions out there that went on non reported!!!

the mechanical fan is a lot less intrusive than the electric.

What is so intrusive about electric fan?

You get an electric fan you plug it in and call it a day. Wait! if you want to turn it on at a certain temperature then you install a temp sensor switch, but wait! if you really want to dial it in at a more precise controlled temperature then you replaced the temp sensor switch a variable one. BTW, don't forget the fuse...

If you do a cooling overhaul every 80-90K, these parts (fan clutch, fan blade) do not have a chance to blow up.

I swear, you must have been paid for every time you said ^ lol!

Originally Posted by cn90

If you do a cooling overhaul every 80-90K, these parts (fan clutch, fan blade) do not have a chance to blow up.

My fan clutch, WP,thermostat,hoses and reservoir were replaced less than 10k miles ago. The radiator was replaced this past May. Overhauling these parts does not guarantee against this type of failure.

Through out college, I drove a 1994 Pontiac Grand Prix. I bought it with 110K and donated it a few months ago with 230 K miles on it. Not a single cooling component needed to be replaced. Never overheated once either. I'm sure I could have put another 100K miles without any issue if I had decided to keep the car.

My point is a cooling system is such a critical part of a car that it should not have as many and frequent failures as the E39 does. I think the E39 cooling system can be improved upon significantly and I intend to do that.

Originally Posted by 16valex

Can you imagine the amount of fan explosions out there that went on non reported!!!

That would be awesome info to find. However I suspect BMW had a relative high number of reports of this nature hence their switch from a mechanical to an electric fan

Schi-tzo,

One thing that gets lost in the discussion of cooling overhaul is the WP Pulley itself.
The BMW techs at dealer told me they change the WP Pulley at 120-140K or so.

Sure enough I went home and saw a small crack in my WP Pulley at 110K, and I replaced it.

Your root cause might have been a cracked WP Pulley.

PS: Schi-tzo, Every time I type your username, the forum software censored it LOL. The software confuses your username with poop LOL.

This is an example of cracked WP Pulley. This is all you need to inflict the damages you mentioned in your original post, even if everything else in the cooling system is new!