[JetwashBen]

Hi,

I've pretty much had this slight squeal on the engine for about 12months if I'm right but it's got a little more noticeable in the last week or so with the cold weather, I used to notice it would subside with a few hours of driving but always there to hear if you didn't have the radio on or the Mrs waffling.. Obviously with the chain issue on this engine I always thought the worse but a few days ago while listening to it I realised the sound was identical to an issue we had with one of our Transits, with that we had the serp belt replaced and even a new pulley but it remained until we pushed for the garage to replace again with genuine Ford pulleys and we never had the problem again so just wondering if this could be a similar case and what you guys think??

Thinking of picking up some anti belt slip tomorrow and giving it a try..

Let me know what you think, any advice would be greatly appreciated.
Cheers
Ben

Vid here

https://youtu.be/kmf9p98r2tY

 

[GarnZ]

Ben, there is a noise that is prevalent on BMW's that have a "over-run" alternator pulley. The pulley become seized and although still functions as a normal pulley, emits a noise. Most mechanics don't believe that this pulley is the culprit.

It happens initially when the engine is cold and becomes inaudible when in neutral, however, when in Drive or Reverse it is noticeable.

RegardZ.

 

[GarnZ]

Here is an extract of part of the post on Alternator Pulley ~ E87 120i, back in July 2015.....

I had the job done on the E87 Hatch auto (2005).
The job consisted of .. new serpentine belt and replace alternator pulley.
As mentioned, this pulley is called a "cush' "pulley, a "free-wheel" or an "over-run" pulley. It has seized causing a noise when cold starting and engaging in F and R.
The noise has now gone!

Here's a pic of the culprit

http://smg.photobucket.com/user/garn/media/a649224d-c52f-4c0b-ad21-7d280d06f44a_zpsa4qzzy29.jpg.html

This pulley screws onto the alternator shaft and is designed to drive the alternator via the belt. When the engine stops or slows, the pulley allows the alternator to free wheel, until running out of momentum. However, these pulleys, in some cases, at about 60 - 80K, cease to operate and the internals seize.
Now, this in itself is not a big problem, as it would just act as fixed pulley (like they did in yester-year). If however, the internals, which must consist of small rollers, mal-functions and the pulley overheats, it can melt the thread and shoulder of the alternator spindle. That's my version anyway!

BTW, there are many makes of cars with this 'cush' pulley and they can be troublesome.
Many thanks to Rammie for his research into this noise problem.

RegardZ.

 

[JetwashBen]

Thanks mate, so what do you suggest I do now? New alternator? Or can I do something to help in the meantime? Come to think of it I've had a few occasions when the battery warning has come up after only a short while with turn off but I just put that down to the Mrs and her short runs.. Power output still seems ok at 12v-14v so seems to be still functional as you say.

Don't know if this is any help but blowers have started emitting a low squeal too on low blow?

 

[GarnZ]

I'm suggesting that the alternator PULLEY is the problem, not the alternator.
So if the noise is similar to this..
OK ready for a trial... "E87 Noise at Cold Start in "D" and "R".

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You only need to replace special pulley and while you are at it replace the serp belt.
RegardZ.

 

[JetwashBen]

Cheers, is it something I can do myself if I can source the part or best to let a garage do it? And is there any danger to the car while it is in this state?

 

[JetwashBen]

I've had a look and the part seems fairly easy to get hold of on eBay, the car is now on 104k so makes sense it would be this.. I've changed alternators and serp belts in the past so I'm thinking this could be something I can tackle myself over a weekend and save on labour costs..

I'm still ok doing a few hundred miles in the meantime right? It's not eventually going to lock up or anything?

Thanks for all your help mate and pointing me in the right direction, much appreciated.

Have a great weekend

 

[GarnZ]

If its the alt pulley, you need a special (simple) tool to get it off, most mechanics have them. Not an expensive job. Pulley is about $100 Aust, avail on ebay both tool and pulley.
You will know if its the pulley when you remove the serp' belt, by carefully wedging the alt armature and seeing if the pulley will over-run. There is a video on this fix.

http://www.e90post.com/forums/showthread.php?t=1080557

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RegardZ.

 

[JetwashBen]

Hi, just a quick update and question..
Had a look on eBay and contacted a few suppliers on there but nobody seemed to have the part for my model so got in touch with a local supplier of parts and they got one in for me, looks like the one above but when I just took a quick look at the one on the car it doesn't seem to have the 33groove bit on it like the part given? It has the torq bolt in the middle but a black bolt around it instead of the 33groove bit?

Sorry if this is a dumb question but just want to be sure before I make a start on it, only chance I'm going to get to do it is this Sunday while the Mrs is at work and don't want to be caught short.

Thanks,
Ben

 

[GarnZ]

here is the eBay heading..
ALTERNATOR OVERRUNNING PULLEY BMW 120I E87 E88 N43B20 125I 3.0 N52B30 130IE87
Spec:
DESCRIPTION: OVERRUNNING ALTERNATOR PULLEY
TYPE: 7PK
WIDTH: 34.40MM
OUTSIDE DIAMETER: 49MM
INSIDE DIAMETER: 17MM
TOOL OAPT33
OAP CONNECTION TYPE: 33 TOOTH SPLINE

http://www.nahux.com/npower

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Color: BLACK
Description:

http://www.nahux.com/npower

" onclick="window.open(this.href);return false;
Overrunning alternator pulleys are becoming increasingly popular on late model petrol and diesel engines, due to the
increasing drive belt speed and engine vibration fluctuations. An overrunning alternator pulley is used to smooth out
rotational irregularities on the alternator, which is caused from rapid acceleration, deceleration and even shut off.
During normal operating conditions these alternator pulleys can be rotating up to 18,000rpm and with major RPM
fluctuations unit failure can lead to belt noise, vehicle vibrations and also alternator or drive belt failure.
Nuline have developed a heavy duty replacement clutch pulley to disengage the alternator so it free spins during
rotational irregularities.

How does the Nuline overrunning alternator pulley work?
When the Nuline overrunning alternator pulley is rotated in the normal operating direction it connects to the alternator
working as a normal pulley. But during deceleration the pulley disconnects from the alternator shaft, allowing the
alternator to free spin. This is done by a special one way bearing that is mounted inside the Nuline overrunning
alternator pulley.
Advantages of using a Nuline overrunning alternator pulley
• Heavy duty designed for long service life
• Dampens drive belt vibration
• Reduced belt slippage during rapid acceleration or deceleration
• Reduced stress on drive belt and other accessory drives
• Increased alternator and drive belt life
• Reduction of drive belt noise
• Improvement in variation of drive belt tension

Signs of an overrunning alternator pulley failing
• Unusual drive belt noises
• Unusual vehicle vibrations
• Steering shudder
• Alternator not charging battery

Checking the overrunning alternator pulley *******
• Remove drive belt
• Check pulley for chips, dents or damage to belt grooves
• Check for excessive bearing movement
• Rotate Alternator pulley in normal operation direction, pulley should lock up and turn alternator shaft
• Rotate alternator pulley in opposite direction, it should spin freely without the alternator shaft moving
• Rotate the pulley in the free spin direction, it should feel smooth not roughhttp://

http://www.nahux.com/npower

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RegardZ ~ Garn
Ring a Bearing place! Or, talk to a local mechanic after checking ******

 

[JetwashBen]

That is the part I've got mate, it just doesn't look the same as the one on the car.. Will get you some pics to explain myself better

 

[JetwashBen]

im still not home yet so put this together quick from my ipad, I've just put it into a quick blog on the company website, will take it down once you have had a look so my customers don't start wondering what's going on

http://westwirraljetwashservices.com/2016/01/20/118d-alterantor-pulley/

 

[GarnZ]

You say that previously you have replaced the alternator.... was that this car?
By the pic it looks like that pulley may have been modified and poss' fitted with an ordinary pulley (non- over-run type) or it may have a different shaft...... This is worst case scenario! Just be ready for this situation.

Test over-run pulley as stated above ****.
If not working or seized, pull off belt and perhaps remove alternator.
Change pulley ... Torque up and fit alternator back in position.
hopefully that 1/2 inch plug is just that, a plug!
RegardZ.

 

[JetwashBen]

No, this is the original alternator I got with the car. I've changed alternators on the vans in the past but this is the original one I got on the car. But I did watch a vid on YouTube of a guy doing a belt change on the same car as mine and although it only scans past quick it looks like he has the same fixture.. That vid is here if you want to check it out

http://youtu.be/rsM8KIc4Q6k

I want to do the repair myself as I enjoy the work and it's fairly straight forward, just don't want to get caught short in the time period I have and being a Sunday.

.. I've just included a pic to that blog now of the Haynes manual I have, it shows both types in there, mine bottom right..

 

[JetwashBen]

While I haven't yet taken the the belt off or tried the pulley I do know the squeal is coming from it, with it sitting at the top of the engine you can get your ear quite close so I'm 99% sure it's coming from that pulley..

 

[GarnZ]

I didn't see any reference to the over-run pulley in "Haynes".
However, I'm sure a 2010 car will have that bearing.
Note, it usually has a black plastic cap ref top photo.
BTW, any auto electrician will have seen that type of bearing on Bosh alternators
If you have trouble removing pulley drop the whole alternator into an auto electrician it will take him 5min max. Then say, can you fit this pulley? While you are there.
Good luck & regardZ.

 

[Matt88]

I have exactly the same noise on mine and was looking for a cause.

In first or second if I go to about 2k rpm then let off the accelerator you can hear it really loud when the engine revs down.

I assume this will be the same cause in a manual?

 

[JetwashBen]

Ok mate, I've spoken to a few people this morning now and a lot of the suppliers either didn't have a clue about it or just pointed at the over run pulley I have already been supplied with but after speaking with my usual garage and auto electrician it looks like I've been given the wrong part and could do more damage than good.. Auto electrician says he see's more over run pulleys on the petrol BMWs and Diesels tend to come with the solid state pulley like mine.. He reckons the sqealing could be just a dry pulley, worth taking off and giving a little bit of a greasing while I do the belt.

 

[JetwashBen]

Hi matt88,

Only just noticed your post, that's how mine started last winter, a slight noise around 2k rpm which had me thinking the worst in regards to the timing chain problem but it subsided a little over the summer, still there but not as evident. Over time it's spread to giving off a squeal in idle too and doesn't really change much with revs anymore.. Going to give it a quick spray later with some ptfe lubricant when I get home from work and go for a quick drive, see if there is any change in the sound, if so then I can hopefully just grease the bearing/pulley while I'm doing the belt change and see how it goes.

 

[GarnZ]

Ben, agree with you, doesn't look like an over-run pulley on video.
Depending on postage to Australia (NSW), I'm interested in buying the pulley so you can at least recoup some of your expense.
RegardZ