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2003 BMW M3
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50 Posts
Discussion Starter #1
I changed out my fan clutch last week due to it going bad. I take it for a test drive after the job was done and everything was okay. A week goes by, I go to the store and when I turn my car on, I hear a ticking sound. I popped my hood and saw that the fan was hitting the shroud. That has never happened before. The part that connects to the water pump was wobbling way too much, as I can visually see it. I took my chance and drove it back home (5mins away). I noticed the wobble stopped when I got home like it never happened. Anyone know why this is happening? Is my water pump going bad? Bearing in water pump going bad?
 

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2003 BMW 325CI convertible, Oct '02 prod. date, 111K miles
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i would certainly remove the fan, belts and check the pump. There lots of posts about refreshing the coolant system, including the pump, to avoid a major system failure.
 

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The water pump doesn't have a bearing for the fan. Either you got a faulty fan clutch, or you didn't tighten it down correctly. It's reverse thread so there's a chance the engine tightened it while running. Retighten it by hand. If it gets loose again you have a faulty fan clutch

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2003 BMW M3
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Discussion Starter #4
The water pump doesn't have a bearing for the fan. Either you got a faulty fan clutch, or you didn't tighten it down correctly. It's reverse thread so there's a chance the engine tightened it while running. Retighten it by hand. If it gets loose again you have a faulty fan clutch

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I took it for a test run and the fan smashed into my radiator and blew. Piece went flying. Fluid on the road. Bad. Back to the lab I go.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Unfortunate.
The two bearings of the water pump, support the fan/fan clutch assembly.

If it was a OEM clutch, (have not seen a wobble yet) likely the issue was a pump bearing going bad?
As mentioned they are reverse thread and self tighten. Albeit need a slight tap to ensure that they stay on. If not, under the right conditions it can roll off.
Was the clutch still attached?

They last very long and one of the slowest moving pumps in BMWs inventory, therefore I'd strongly suggest genuine for a replacement.

You need to get to the root of what happened, so you don't repeat it.
 

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I took it for a test run and the fan smashed into my radiator and blew. Piece went flying. Fluid on the road. Bad. Back to the lab I go.
I can't imagine the fan going into the radiator unless the shaft of the water pump broke or the impeller came loose. You'll just have to get in there and find the root cause, either the water pump or the fan clutch. Hint..if the fan clutch is whole, i.e., the threaded part is still there but the clutch not attached to the pump shaft, it's likely improper installation.
I took it for a test run and the fan smashed into my radiator and blew. Piece went flying. Fluid on the road. Bad. Back to the lab I go.
serp belt drives fan pulley bolted to water pump by 4 bolts.
water pump drives viscous coupling attached by left hand thread.
viscous coupling drives fan attached by three M6 bolts.

The parts fiche shows a flange on the fan that goes behind the viscous coupling so generally if one or more of the three bolts holding the fan to the VC get loose or lost, the VC just turns and the fan doesn't. The flange would have to fail for the fan to go into the radiator and even then there is no drive to the fan to pull it into the radiator.

The serp belt driven pulley is held to the water pump shaft by 4 bolts...if the bolts fail (unlikely for 4) the pump is not driven and the fan is unlikely to drive into the radiator. Unlikely by a LOT.

If the VC fails and locks up (and it would have to fail because the LH thread tightens with motor operation and so is unlikely to come off ) the fan could be driven forward into the radiator...it would be obvious what happened because the VC/waterpump shaft are separated, water pumpshaft still on engine.

A rare black swan would be the WP impeller separates and the shaft is pulled forward and out of the WP as well as the WP bearings...you would then see the WP shaft, still attached to the VC/fan.

Another black swan is the drive flange on the WP shaft separates (it's pressed on IIRC) and allows the fan assembly to march into the radiator...you would then seen the flange still attached to the fan assembly and the bare WP shaft still in the WP/engine.

Look and you shall see.
 

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2003 BMW M3
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Discussion Starter #7
I can't imagine the fan going into the radiator unless the shaft of the water pump broke or the impeller came loose. You'll just have to get in there and find the root cause, either the water pump or the fan clutch. Hint..if the fan clutch is whole, i.e., the threaded part is still there but the clutch not attached to the pump shaft, it's likely improper installation.


serp belt drives fan pulley bolted to water pump by 4 bolts.
water pump drives viscous coupling attached by left hand thread.
viscous coupling drives fan attached by three M6 bolts.

The parts fiche shows a flange on the fan that goes behind the viscous coupling so generally if one or more of the three bolts holding the fan to the VC get loose or lost, the VC just turns and the fan doesn't. The flange would have to fail for the fan to go into the radiator and even then there is no drive to the fan to pull it into the radiator.

The serp belt driven pulley is held to the water pump shaft by 4 bolts...if the bolts fail (unlikely for 4) the pump is not driven and the fan is unlikely to drive into the radiator. Unlikely by a LOT.

If the VC fails and locks up (and it would have to fail because the LH thread tightens with motor operation and so is unlikely to come off ) the fan could be driven forward into the radiator...it would be obvious what happened because the VC/waterpump shaft are separated, water pumpshaft still on engine.

A rare black swan would be the WP impeller separates and the shaft is pulled forward and out of the WP as well as the WP bearings...you would then see the WP shaft, still attached to the VC/fan.

Another black swan is the drive flange on the WP shaft separates (it's pressed on IIRC) and allows the fan assembly to march into the radiator...you would then seen the flange still attached to the fan assembly and the bare WP shaft still in the WP/engine.

Look and you shall see.
I removed my skid plate and I found ball bearings and other tiny pieces of the water pump down there.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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There ya' go.
Mileage dependent and if you live in a state where there's emission testing I'd suggest the following:

#1, 3, 5, 6 and two of # 8.

If you're in an emissions testing state, I'd also recommend #4 the housing. There is a seal (non replaceable) inside the housing that wears. If worn, when the thermostat is closed, too much coolant gets past. This sometimes can trigger a thermostat plausibility code. Sux, but you only want to do the job once.
Do yourself a favor and at the very least buy a genuine pump, seals and the housing. (if needed)


While you're in there: Do yourself a HUGE favor and tighten up (just a little) the pin boss for the left side chain guide. The crush seal often weeps small amounts of oil and creates a "mystery" leak. Don't get the urge to remove it and replace the seal, the rail could move. Just a little tighter does the trick for another 100K.


# 10, resting on the side of the head, hidden by the thermostat housing.

 

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2003 BMW M3
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Discussion Starter #9
There ya' go.
Mileage dependent and if you live in a state where there's emission testing I'd suggest the following:

#1, 3, 5, 6 and two of # 8.

If you're in an emissions testing state, I'd also recommend #4 the housing. There is a seal (non replaceable) inside the housing that wears. If worn, when the thermostat is closed, too much coolant gets past. This sometimes can trigger a thermostat plausibility code. Sux, but you only want to do the job once.
Do yourself a favor and at the very least buy a genuine pump, seals and the housing. (if needed)


While you're in there: Do yourself a HUGE favor and tighten up (just a little) the pin boss for the left side chain guide. The crush seal often weeps small amounts of oil and creates a "mystery" leak. Don't get the urge to remove it and replace the seal, the rail could move. Just a little tighter does the trick for another 100K.


# 10, resting on the side of the head, hidden by the thermostat housing.

Is it possible that any of those metal pieces entered my engine? I bought a new water pump, fan, thermostat, and radiator. Should be here by the end of the week.
 

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2003 BMW M3
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Discussion Starter #10
There ya' go.
Mileage dependent and if you live in a state where there's emission testing I'd suggest the following:

#1, 3, 5, 6 and two of # 8.

If you're in an emissions testing state, I'd also recommend #4 the housing. There is a seal (non replaceable) inside the housing that wears. If worn, when the thermostat is closed, too much coolant gets past. This sometimes can trigger a thermostat plausibility code. Sux, but you only want to do the job once.
Do yourself a favor and at the very least buy a genuine pump, seals and the housing. (if needed)


While you're in there: Do yourself a HUGE favor and tighten up (just a little) the pin boss for the left side chain guide. The crush seal often weeps small amounts of oil and creates a "mystery" leak. Don't get the urge to remove it and replace the seal, the rail could move. Just a little tighter does the trick for another 100K.


# 10, resting on the side of the head, hidden by the thermostat housing.

I’m in south Florida
 

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2003 BMW M3
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Discussion Starter #11
Unfortunate.
The two bearings of the water pump, support the fan/fan clutch assembly.

If it was a OEM clutch, (have not seen a wobble yet) likely the issue was a pump bearing going bad?
As mentioned they are reverse thread and self tighten. Albeit need a slight tap to ensure that they stay on. If not, under the right conditions it can roll off.
Was the clutch still attached?

They last very long and one of the slowest moving pumps in BMWs inventory, therefore I'd strongly suggest genuine for a replacement.

You need to get to the root of what happened, so you don't repeat it.
The clutch was still attached.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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There are actually two bearings, one at either end of the shaft. 99.9% of the time, it's the nose bearing that fails.
They drop out onto the floor.
 

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2003 BMW M3
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Discussion Starter #15
There are actually two bearings, one at either end of the shaft. 99.9% of the time, it's the nose bearing that fails.
They drop out onto the floor.
Cost me a pretty penny lol she should be up and running by the weekend, as long as my parts get here. Thank you for the help.
 

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2003 BMW M3
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Discussion Starter #16
Cost me a pretty penny lol she should be up and running by the weekend, as long as my parts get here. Thank you for the help.
Is it possible for parts of the water pump to break, go into my engine, and destroy it? Just found these pieces in the hole that connects to the water pump. Has me very worried.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Well that's a catastrophic failure. Can happen but the pieces are usually large and not tiny.
Furthermore any bearing it impeller part will not find it's way up to blocking any criticy small orifice.
 

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2003 BMW M3
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Discussion Starter #19
Well that's a catastrophic failure. Can happen but the pieces are usually large and not tiny.
Furthermore any bearing it impeller part will not find it's way up to blocking any criticy small orifice.
Any suggestion as to how I should remove those small black pieces of plastic?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Or impeller.
I hate cell phones.
 
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