Drive belt pulley question

[Irhase46m3]

Hi There - Does anyone have the part number for the pulley's being used (not the deflection pulley)? Correct me if im wrong but i dont see a point in replacing the entire AC/PS pulley assembly (with the arm) and the WP/ALT pulley assembly - Wouldn't it be possible to just replace the pulley's? Has anyone attempted to do this?

I find it hard to believe that these pulleys are only made for the e9x/e6x M's

Best,
Irhase46m3

[tdott]

Taken from the other forum:
1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
1 Production date on or after 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6DK1100
2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
3 BMW E9X M3 A/C Belt Tensioner Strut Only 4/29/2008+ = INA F-239109.01
6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100
6 Built on or after 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = Only available from BMW 11287841531

1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
3 BMW E9X M3 Alternator Belt Tensioner Strut Only = INA F-239110.04

I replaced the following on my early 2008 and they were not expensive if you buy the INA replacement.

• 1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
• 1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
• 2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
• 2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
• 6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100

However if you have the later style deflection pulley that is only available from the dealer, it will cost more than all of the other ones and you'll need the doubled sided AC belt.

[IamFODI]

Taken from the other forum:
1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
1 Production date on or after 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6DK1100
2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
3 BMW E9X M3 A/C Belt Tensioner Strut Only 4/29/2008+ = INA F-239109.01
6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100
6 Built on or after 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = Only available from BMW 11287841531

1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
3 BMW E9X M3 Alternator Belt Tensioner Strut Only = INA F-239110.04

I replaced the following on my early 2008 and they were not expensive if you buy the INA replacement.

• 1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
• 1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
• 2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
• 2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
• 6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100

However if you have the later style deflection pulley that is only available from the dealer, it will cost more than all of the other ones and you'll need the doubled sided AC belt.

Nice. Thanks, tdott !

[Irhase46m3]

Hi There - Thank you for posting this, i just spent 7hrs looking for these part numbers over the weekend lol. Looks like i was correct, i ordered them and i will be installing them soon. each pulley was $20~ from FCPEuro.

[Irhase46m3]

Taken from the other forum:
1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
1 Production date on or after 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6DK1100
2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
3 BMW E9X M3 A/C Belt Tensioner Strut Only 4/29/2008+ = INA F-239109.01
6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100
6 Built on or after 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = Only available from BMW 11287841531

1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
3 BMW E9X M3 Alternator Belt Tensioner Strut Only = INA F-239110.04

I replaced the following on my early 2008 and they were not expensive if you buy the INA replacement.

• 1 BMW E9X M3 alternator/water pump serpentine belt = Continental 6K1460
• 1 Production date before 4/29/08 BMW E9X M3 AC/power steering serpentine belt = Continental 6K1065
• 2 BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
• 2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100
• 6 Built before 4/29/08 BMW E9X M3 deflection pulley (aka idler pulley) = INA 5320418100

However if you have the later style deflection pulley that is only available from the dealer, it will cost more than all of the other ones and you'll need the doubled sided AC belt.

Quick question, from all the research that i did, it pointed out that the AC pulley was the same part number as the water pump pulley, I essentially ordered two of the same. Even looking at photos from BMW showed that it was the same pulley part number for both. Could i ask how did you come up with 5320557100? Do you know for a fact if its an interexchangable part or if it wont fit? Trying to determine if i should order 5320557100 right now.

All Best,
Irhase46m3

[Irhase46m3]

They are all the same pulley part number, the two on the left are the pulleys pulled out of the car (original bmw) - The one on the right is the fcpeuro replacement for PS/AC - Confirmed they are all the same pulley.

Just to clarify this is for an early production 2008 car, before 04/29/08 - Hope this helps anyone!

[tdott]

Quick question, from all the research that i did, it pointed out that the AC pulley was the same part number as the water pump pulley, I essentially ordered two of the same. Even looking at photos from BMW showed that it was the same pulley part number for both. Could i ask how did you come up with 5320557100? Do you know for a fact if its an interexchangable part or if it wont fit? Trying to determine if i should order 5320557100 right now.

All Best,
Irhase46m3

What do you mean by water pump pulley? That one doesn't have a bearing in it and not the same as the AC tensioner pulley. Pictured above.

[Irhase46m3]

What do you mean by water pump pulley? That one doesn't have a bearing in it and not the same as the AC tensioner pulley. Pictured above.

In my car, the AC n Power steering tensioner pulley is the same as the water pump n Alternator tensioner pulley. The photo i posted above shows the original bmw pulleys which are exactly the same for both tensioners. Hopefully im making sense.

[tdott]

In my car, the AC n Power steering tensioner pulley is the same as the water pump n Alternator tensioner pulley. The photo i posted above shows the original bmw pulleys which are exactly the same for both tensioners. Hopefully im making sense.

Ah got it, the WP/Alt tensioner pulley. Thought you meant the water pump pulley itself.

Maybe the same pulley may also work, but the one I used is:
2 BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100

[tdott]

I found this:

After plenty of research some serious money savings on tensioner pullies was found. Bolt and washer just need to be removed.
BMW does not list the pulley separately and wants you to pay $180 for the pulley and bracket.

These two pullies are different sizes, 70mm OD for the alternator/water pump tensioner pulley and 65 OD for the power steering/AC compressor tensioner pulley.
BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100

[Irhase46m3]

I found this:

After plenty of research some serious money savings on tensioner pullies was found. Bolt and washer just need to be removed.
BMW does not list the pulley separately and wants you to pay $180 for the pulley and bracket.

These two pullies are different sizes, 70mm OD for the alternator/water pump tensioner pulley and 65 OD for the power steering/AC compressor tensioner pulley.
BMW E9X M3 A/C Belt Tensioner Pulley Only = INA 5320557100
BMW E9X M3 Alternator Belt Tensioner Pulley Only = INA 5320342100

Im not sure if that is true, i measured both pulleys and they are the same in diameter. Also, they are the same part number, you can see it in the photo above. Im not sure if that applies to the lci or post 04/29/08 cars but at least on mine it was the same. Car only has 50k miles so this is the first time doing the pulleys.

[tdott]

Im not sure if that is true, i measured both pulleys and they are the same in diameter. Also, they are the same part number, you can see it in the photo above. Im not sure if that applies to the lci or post 04/29/08 cars but at least on mine it was the same. Car only has 50k miles so this is the first time doing the pulleys.

Someone could have already changed it. afaik there were mentions of it people using the 65mm OD pulley on both because the correct sized one wasn't found until later, or maybe not everyone knew about it. Also because the alt/wp belt is usually fairly tight and difficult to get on the small pulley might have made install easier.

The good thing is they both should work fine.

I owned my e92 since 2012 and recently crossed 120k and changed all the pulleys during a cooling system overhaul and did confirm my tensioner pulley were different sizes.


Also AFAIK and according to realoem, only the AC/PS idler pulley, belt and PS pump changed over the years. So if that is true then the tensioner pulley's have no mention of being changed throughout the years so pre-lci or lci, or +4/08 shouldn't matter.

[Irhase46m3]

Someone could have already changed it. afaik there were mentions of it people using the 65mm OD pulley on both because the correct sized one wasn't found until later, or maybe not everyone knew about it. Also because the alt/wp belt is usually fairly tight and difficult to get on the small pulley might have made install easier.

The good thing is they both should work fine.

I owned my e92 since 2012 and recently crossed 120k and changed all the pulleys during a cooling system overhaul and did confirm my tensioner pulley were different sizes.


Also AFAIK and according to realoem, only the AC/PS idler pulley, belt and PS pump changed over the years. So if that is true then the tensioner pulley's have no mention of being changed throughout the years so pre-lci or lci, or +4/08 shouldn't matter.

Sorry but thats not the case, i have owned the car since basically new and i barely drive it. With 120k miles on the clock, isnt it possible that your pulleys got replaced multiple times?

Additionally, the base of my research is as follows:

pulley part number from bmw AC/PS:




pulley part number from bmw WP/ALT:





All pulleys lined up, far right is the replacement:



As you can see all the part numbers match.

So unless BMW ran out of the 70mm diameter pulley, im not sure what else to say :-/ - In any event, we are going round in circles here, i think its best for people to order 3 pulleys to avoid downtime and compare them before installing them. Or if you have the cash just order the replacement tensioners that come with the pulley from BMW.

Best,
Irhase46m3

[tdott]

In any event, we are going round in circles here, i think its best for people to order 3 pulleys to avoid downtime and compare them before installing them. Or if you have the cash just order the replacement tensioners that come with the pulley from BMW.

Yes, not worth arguing semantics when they both work.

Not sure any of us can confirm why there is a difference. I can only say mine haven't been changed in the last 10 yrs in my ownership and it's not likely they were changed early in the cars life with low mileage. I'd say it is more age based than mileage based.

It's just the tensioner pulley, so the size doesn't over-drive or under-drive any of the accessories. Really doesn't have much impact other than how far the tensioners sits when installing the belt and when at rest and it's only a 5mm OD difference.

[Irhase46m3]

tdott - Would you happen to have the torque spec for the pulley's?