DIY: Re-grease the 3 belt pulleys

cn90 · Jul 17, 2011

After 30K miles, I decided to remove all 3 pulleys and re-greased them. I am glad I did.
The grease is still there but already dried out quite a bit. Each pulley is about $25 (or $75 total), so by doing this maintenance, you significantly prolong the life of these 3 pulleys.

Tools needed (Different years may require different tools):

- Thin 32-mm Fan Clutch Wrench

- 16-mm socket for Idler Pulley

- 5/16" or 8mm Allen Socket (some years use Torx socket, check with mirror to be sure)

- 1/2" Breaker Bar and Adaptor from 1/2"---> 3/8"

- Grease, I use wheel-bearing grease, some people prefer "high-temp grease", your choice. Since I will be doing this every 30K, I simply use wheel-bearing grease.

- Large socket 30-mm and 32-mm to seat the pulley seal back in.

- Pick Tools

PROCEDURE:

1. Remove Plastic splash shield (Phillips screw driver, 9 screws total).

2. Remove Fan Clutch (32-mm wrench, REVERSE thread, so strike to CCW to remove the Fan Clutch). Set the Fan Clutch/Fan Blade combo INSIDE the Fan Shroud.

3. Make a note of Belts Routing, draw them on a piece of paper. I engrave Belts Routing on my Air Filter Housing Plastic Cover so at a glance, I know where the belt is supposed to go. I also wrote Engine Oil Change = 7.0 Qt so when I change oil don't have to open the owners manual to check for oil capacity LOL.

4. Tensioner Pulleys x2 (AC and Main Belt): 5/16" or 8mm Allen Socket. Watch the large washer on the back side of the pulley and do NOT lose it.

5. Idler Pulley: 16-mm socket.

6. To remove pulley's seal: use the pick tool and hook it on the INNER side of the seal, then turn the pick tool 90 degrees and gently pull it out. Work slowly to avoid damage to the seal.

7. You can go to the extent of soaking the pulley in gasoline to dissolve everything, let it dry and repack with grease. I simply cleaned old grease off where I can (Q-tip); then pack new grease using my finger.

Then gently drive the seal back in. I used mostly 30-mm socket because it fits perfectly.
When removing the seal, pay attention to which side is which! The Black side faces outward. If confused, then look at the INNER Lip: it is slanted outward.

Re-installation is straightforward! Enjoy the quiet pulleys!

194449 · Jul 18, 2011

#2, you might want to say CW.... or toward the driver-side in the US.

#6 That's the way to do it but the older the pulley, the more likely that seal will be brittle and crumble....

cn90 · Jul 18, 2011

pleiades said:
#2, you might want to say CW.... or toward the driver-side in the US...

Thanks!

#2 I just fixed the typo error.

Thanks again!

vetaldj · Jul 18, 2011

cn90, you are THE MAN!!!
As always, just in time! I'm planning to do so soon (I want to change belts so I will have access to pulleys as well).

One question, I think mine pulleys as stock but I don't have any sound from them (well, just one is under questions - AC one, I have very strange sound when I turn AC on now...) and they look ok as well, do you think that grease will work or it's better to change them all together?

Thanks!

cn90 · Jul 18, 2011

Check the bearing, if slight play = normal. Then re-grease it.

Too much play: replace it.

bluebee · Jul 18, 2011

cn90 said:
Check the bearing, if slight play = normal. Then re-grease it.

Excellent suggestion to re-grease the pulleys every so often!

Here, for the record, are what my 'spinning tests' showed on old (~90K miles) & new pulleys & the idler roller:
- One users' example of total electrical failure (AAA towed away) alternator repair (1)

cn90 · Jul 18, 2011

Another thought.

In contrast to wheel bearing, the pulley bearings are:
- smaller
- have less grease packed from factory
- constantly heated to high temp such as 200F.
- spinning all the time at high speed: the diameter of these pulleys is rather small compared with the crank pulley, so if the crank pulley moves once, these pulleys probably move 3 times. At engine speed of 3000 rpm, I would not be surprised if these pulleys run at 9000 rpm (simple math conversion of pulley diameters)!

JimLev · Jul 18, 2011

CN, you may want to try some Timken Ultra-High Speed Spindle Grease next time. A bunch of us on Roadfly tried it out about 3 months ago. Eurodavid found the stuff and posted it. Don't know why they sent the peanuts with the grease, should have included a few beers too.

cn90 · Jul 18, 2011

Thanks Jim,

I am aware of that thread on roadfly by EuroDavid.

The reason I did not want to try the Timken Ultra-High Speed Spindle Grease is that:
- At factory, the bearing is probably packed with High Speed Spindle Grease anyway, and yet it still dries out at 30K miles. My theory is the pulley is subject to engine heat + high-speed spinning (9000-15000 rpm), and these factors basically accelerate grease lifespan.
- I plan to re-grease the pulleys every 30K miles. It is an easy job, so no big deal.
- The pulleys are not that bad in prices: $25/each, worst case scenario I simply replace the pulley.
- The price of Timken Ultra-High Speed Spindle Grease is $16 as you said.
- Then the last question: is Timken Ultra-High Speed Spindle Grease better than wheel bearing grease? Nobody has an answer.

These are the reasons I stick to wheel-bearing grease because it is free (I have it at home) LOL.

bwaysteve · Jul 18, 2011

A question about the pulley that attaches to the alternator.When reinstalling does it only fit one way with the long bolt in the alternator?Mine has only about 1/4 in. of clearance between the pulley and the tensioner.

aioros · Jul 18, 2011

Can you post a picture?

bwaysteve · Jul 18, 2011

pic of pulley

Here is the pulley and the proximity to the tensioner

cn90 · Jul 18, 2011

Steve,

On the back side of that pulley, there is a notch, it must fit in the corresponding hole.

cn90 · Jul 18, 2011

This is the correct spacing between the "Idler Pulley" and the "Alternator Pulley":

glemere · Jul 18, 2011

Thanks for help. This seems to really make sense. I will give this a try - Gary

cn90 · Jul 18, 2011

bwaysteve,

Another pic from the DIY (listed above) to show the spacing:

bwaysteve · Jul 18, 2011

C90.Thanks for the pic.I got all back together,started, and belts started squeaking.I removed the idler pulley and and looked on the back.There is a little bump that sits in an indent on the alternator.On the alternator there is a little round hole and a u shaped hole.I assume the bump on the pulley goes in the round hole.Trying both "holes" I still do not have the clearance you show in the pics.(see my pic 99 528i above).This has got to be a simple mistake I am making,but can't figure it out. Thanks

cn90 · Jul 19, 2011

bwaysteve,

Now I know. The only way to have your problem is to forget to install the LOWER alternator mounting bolt. During install, you probably forgot to install the LOWER alternator mounting bolt. See related info here:

http://www.forum.bimmerfest.com/showthread.php?t=414315

This picture will show you the relationship between the Idler Pulley and the Alternator:

bwaysteve · Jul 19, 2011

Still trying to figure out why the belts on the pulleys are almost touching and squeeling(not before repair was done).With the spring tensioner is there another way to tighten the belt on the 528i?

bwaysteve · Jul 19, 2011

Thanks C90 Top and bottom bolt are installed and the PS pump bolted in aligned.So everything is where it was.

cn90 · Jul 19, 2011

So did you solve the problem yet?

bmw_n00b13 · Jul 19, 2011

Did this to my car when I did the cooling overhaul. Fingers crossed, 15,000km later it's still happy.

Good idea about engraving information. My car is 6.5L to the middle of the dipstick, but I guess the 7 doesn't hurt

JimLev · Jul 20, 2011

CN, the Lucas grease looks pretty good, most of the specs are pretty even.
I suspect the timken grease at 300F for 2000 hrs may be very slightly better, but for $5 the Lucas grease is much better than regular wheel bearing grease.
I have no idea what most of the other spec mean.

bluebee · Nov 6, 2011

For the record, I just added this thread to the bestlinks so that others find it more easily in the future ...

- How to tell if you have mechanical or hydraulic belt tensioners (1) & how to switch from mechanical to hydraulic (1) and what is the difference between the two types (1) (2) & how to rebuild your hydraulic tensioners (1) & how to re-grease your pulleys and rollers (1) & the answer to the question of adjusting the 540i hydraulic tensioners' belt tension (1) (2)

glemere · Nov 7, 2011

After chasing down the sqeek (more like a squeal) for quite some time, I was able to determine that the noise was not coming from the belt system. The 2004 330XI was converted to a hydraulic tensioner which seemed to rule out one noise scenario. Each of the pulleys were examined with the belt removed only to find they were in good working order, ruling out the most likely culprit.
The more the investigation went on, it was discovered that the squeal was eminatting from somewhere below the intake. The squeal would occur for only a few seconds immediately after starting a cooled engine. It turned out that the starter motor failing. The pin was not retracting as fast as it should have and would, embarassingly, reveal itself during a cold start. It is not like me to have anyone work on my car, but to change the starter in this car would have taken much more time than I would have been able to be without a car. With the billed now paid, the car is back to delivering an unequalled performance.

bluebee · Nov 7, 2011

glemere said:
It turned out that the starter motor failing.

That was good detective work.

Thanks for giving us an update, especially since the culprit isn't a common one so it's good for others to be on the lookout for this.

For the record, these are the starter-motor threads (I'll cross reference your post to one of them so that people can more easily find it in the future, long after we're gone):

- Where is the starter motor located (1) & an M52 starter motor DIY (1) (2) & the BMW TIS (1) and an E38 740iL starter motor DIY (1) (2) & how to remove the M52 starter motor without removing the intake manifold (1) (2) & what special tools are needed (1) (2) (3) (4) (5) & where is the starter motor relay (1) (2)

bluebee · Jan 20, 2015

This related thread popped up today ...
> E39 (1997 - 2003) > replacible pully?

nightwinger5 said:
Am i able to remove the pully off of the tensioner. The bearings are starting to rattle a little and i want to get it replaced as soon as possible. Thanks for any help

See also:
- How to tell if you have mechanical or hydraulic belt tensioners (1) & how to switch from mechanical to hydraulic (1) and what is the difference between the two types (1) (2) & how to rebuild your hydraulic tensioners (1) & how to re-grease your pulleys and rollers (1) & the answer to the question of adjusting the 540i hydraulic tensioners' belt tension (1) (2)

cn90 · Jun 28, 2015

Original thread was at 30K on pulleys.

Time to re-grease at 60K. Again, pulleys free-wheel but no noise yet.

This time I was "lazy' (in reality no interest in removing seal), so I use a needle, slid it underneath the seal's lip and injected some grease. Just make sure the seal's lip returns to its original position (the lip is slanted outward a bit where it meets the shaft.

Perfect trick!!! Pulleys no longer free wheel!

Re-installed and all is quiet.

Note that the belts' condition at 60K. I replaced them for peace of mind...

1. The serpentine belt had cracks on the ribs but the shiny side is fine, no cracks. Replaced anyway.

2. The AC belt is a disaster. It had broken chunks of ribs. Replaced anyway.

Whatever you do, once the belts are re-installed, make sure with 100% certainty that they are routed properly and sit on proper pulley grooves. Failure to do so may destroy your engine (belt runs off main pulley and sucked inside the timing chain area!).

Photo op...

DIY: Re-grease the 3 belt pulleys

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