BMW Drive Belts & V-Belts for BMW Z Series E85/6 (2003-2008)

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Your BMW's drive belts are wear items, and will degrade and crack over time. Don't wait until you have a belt failure... don't get stranded! Replacing your BMW's belts, such as the alternator belt, power steering belt, air conditioning AC belt, or serpentine belt is a low cost insurance policy to preventing a break down -- or worse, engine damage. We recommend checking your belts every 10,000 miles. If your belts have excessive cracks, dry rot, missing teeth and/or grooves, are cause noise, it's time for new ones.

While also inspecting your serpentine belts, also check for wear or resistance in the pulleys. The tensioner pulley and deflection pulley are the primary sources for belt squealing. The rubber-isolated pulleys can also break apart, leading to total belt failure. We sell the tensioner and deflection pulleys for the M50 engine family used in the E34, E36, E39, E46, X5, Z3, and Z4.

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Crank Seal Guard - N52/N54/N55/S55
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Turner Motorsport - Corporate Logo
T#:15876877
Part#: 049453LA01-02
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Introducing our Turner Motorsport Crank Seal Guard – the essential shield for your BMW's engine integrity. Safeguarding the heart of your vehicle, this meticulously designed guard offers robust protection for the crank seal concealed behind the harmonic balancer.

Considered an indispensable maintenance component for your BMW, the Crank Seal Guard acts as a crucial defense against a potential and preventable catastrophe involving your accessory belt. Facing the reality of potential oil or coolant leaks in your engine, this guard becomes a reliable barrier, preventing these fluids from reaching the accessory belt. The consequence of a compromised belt includes walking, slipping, fraying, and rubber particles finding their way behind the harmonic balancer and into the crank seal – a scenario that can lead to severe engine failure.

Let's be honest, engine leaks are a common occurrence, and whether your engine is currently leaking or not, the Crank Seal Guard is a proactive measure against future threats. The wear and tear on the accessory belt due to oil and coolant exposure can result in slipping, tearing, or, worst-case scenario, belt snapping – posing a significant risk to your engine's well-being.

Prepare your car for the long haul and protect the vital components, It's not a matter of "if" but "when" your belt will become a problem, and our Crank Seal Guard is your proactive solution. Rigorously tested on N52/N54/N55 and S55 for 100% confirmed fitment, it stands as a reliable guardian for your engine's health. Invest in the protection your BMW deserves with the Turner Motorsport Crank Seal Guard.

Key benefits:

Protect crank seal from rogue accessory belts and their shredded debris
Optimized to fit N52, N54, N55, and S55 engines
Rigid design that fits within the space constraints between the engine block and harmonic balancer
Zinc-coated fasteners for corrosion and oxidation resistance
Design:

Modeled and designed from FARO laser scanning and Solidworks CAD
Manufactured from 6061 billet aluminum
Turner blue anodizing
Installation:

It is a good idea to note how your belt is routed before starting the installation.

2 securing bolts for crank seal guard - Torque value of 20Nm

You will find either 6 or 8 E10 bolts are holding the harmonic balancer depending on the engine.

E10 (P#11237564511) ​
​N52: 6 bolts - Torque value of 25nm
N54: 6 bolts - Torque value of 35nm
N55: 8 bolts - Torque value of 35nm

E10 (P#11237575488)
S55: 8 Bolts - Torque value of 35nm

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Turner Motorsport - Corporate Logo
T#:3465
Part#: PPK-MZ4
In Stock
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$ 266.24 USD
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$ 354.99

This product was last offered at the strikethrough price on
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$ 266.24 USD
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Underdrive Power Pulleys work to 'free up' horsepower. Any accessory that spins from the main drive belt is using up power. That's power that could otherwise be used to move the car. By giving some of that power back to the engine, you can make the car faster! It's like FREE HORSEPOWER !

Underdrive pulleys for your BMW will slow down engine-mounted accessories - the water pump, power steering pump, and alternator*. These systems contribute to 'parasitic losses' - power lost from what the engine could produce if it did not have these systems. Since less energy is used to move them, that power is transferred back to the engine and used to propel the car. Our pulleys give a 10-20% reduction in rotation, releasing up to 11hp on most BMW six-cylinder engines. There's also a small but noticeable improvement in throttle response too! We have done extensive testing and development work, both on and off the track, to ensure that the accessory systems function as they should. On our Racing pulley kits we actually underdrive certain components more so we feel our Street pulleys are an ideal compromise between power/torque gains, reliability, and system performance. Our pulley kits have been on the market for over ten years, and used in all of our own cars, with zero component failures related to their use.

Our pulleys are made from T-6061 aluminum and finished in a durable black hard anodize that is very resistant to wear, chemical exposure, and heat. We designed our pulleys to look similar to the factory parts but also to be stronger and, in most cases, slightly lighter too. For example, With our hardcoat aluminum you will never have to worry about a serious failure of a stock plastic pulley. A 'stealth' approach to aesthetics was our goal and we let the results speak for the pulley design. Installation is straight forward and easy with simple hand tools. Removal of the fan is required for access to the front of the engine. Total install time for a 3-piece pulley set should be around 1.5 hours. A new longer belt is included and we also recommend replacing the separate A/C belt, belt tensioners, and the guide and deflection pulleys at the same time.



Additional Info
Clickhere for example dyno graph

Click here for installation instructions.

Turner Pulley Kit contents:
  • Turner water pump pulley
  • Turner power steering pump pulley
  • new extended length belt
  • instructions

    This underdrive pulley kit fits the following BMW:
    2006-2008 MZ4 Z4 M Coupe / Z4 M Roadster
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    ECS - Corporate Logo
    T#:363707
    Part#: 001977ECS03A
    In Stock
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    This product was last offered at the strikethrough price on
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    $ 99.74 USD
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    Most of the pulleys on your BMW engine are plastic, which become brittle and frail over time and from engine bay heat. A failed pulley could leave you stranded which is why it is vital to inspect the pulleys during routine maintenance. This is an aluminum version of the stock water pump pulley used on the M50/M52/M52TU/M54 engine in the E36, E46, Z3, Z4, and other models. It uses the same hardware and the original belt as the stock plastic pulley. But the aluminum will last much longer.
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    E46 M3, Z4M ECS Tuning Aluminum Water Pump Pulley
    10X Entries Into Our F80 M3 Sweepstakes
    ECS - Corporate Logo
    T#:367060
    Part#: 002778ECS01
    Ships on Dec 18, 2026
    Sale - Save 10% $ 100.99

    This product was last offered at the strikethrough price on
    06-13-2026

    $ 90.89 USD
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    $ 100.99

    This product was last offered at the strikethrough price on
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    $ 90.89 USD
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    Most of the pulleys on your BMW engine are plastic, which become brittle and frail over time and from engine bay heat. A failed pulley could leave you stranded which is why it is vital to inspect the pulleys during routine maintenance. This is an aluminum version of the stock water pump pulley used on the S54 engine in the E46 M3, MZ3, and Z4M. It's the same size and uses the same hardware and the original belt as the stock plastic pulley. But the aluminum will last much longer.
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    Mechanical A/C Belt Tensioner Assembly
    10X Entries Into Our F80 M3 Sweepstakes
    Bremmen Parts - Corporate Logo
    T#:26305100
    Part#: 11281433571
    In Stock
    Sale - Save 21% $ 59.99

    This product was last offered at the strikethrough price on
    05-03-2026

    $ 47.32 USD
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    Mechanical A/C Belt Tensioner Assembly
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    Bremmen Parts - Corporate Logo
    T#:32350880
    Part#: 11287512758
    In Stock
    Sale - Save 15% $ 52.99

    This product was last offered at the strikethrough price on
    09-16-2026

    $ 45.04 USD
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    Bremmen Parts - Corporate Logo
    T#:39497969
    Part#: 11287530314
    In Stock
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    $ 43.24 USD
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    This tensioner keeps the belt for the alternator, power steering, and air conditioning taut to provide maximum performance of each system.
    Bav Auto Ratcheting Serpentine Belt Wrench Kit
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    Bav Auto Tools - Corporate Logo
    T#:580390
    Part#: B8800077
    In Stock
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    Used to retract your serpentine belt tensioner. This kit includes 18mm, 5/8 in, 14mm, 13mm, 12mm, sockets and 3/8 in and 1/4 in drive adapters

    Hydraulic Alternator Belt Tensioner Conversion Kit
    10X Entries Into Our F80 M3 Sweepstakes
    Packaged by Turner - Corporate Logo
    T#:15710833
    Part#: 11287838797-KT
    Back Ordered
    Sale - Save 1% $ 165.99

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    The original mechanical design is has been discontinued by BMW. So now Turner offers this complete hydraulic tensioner conversion kit for your BMW alternator/water pump/power steering belt. Changes the old style mechanical design to the updated hydraulic design recommended by BMW. Includes the following parts Hydraulic Tensioner Adjusting Pulley Caps & Dust Guards Securing Hardware
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    Packaged by Turner - Corporate Logo
    T#:23482931
    Part#: S54KEVACCKT
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    Eliminate your squeaking accessory belt pulley and cracked drive belt with this upgraded accessory belt service kit! This kit includes the ECS Kevlar Reinforced Drive Belts, tensioner assemblies, and new tensioner pulleys. ECS Tuning's Red Kevlar Accessory Belts are both an aesthetic improvement and a performance alternative to a traditional belt. Kevlar-reinforced belts experience less elongation over time minimizing the amount of belt adjustment needed as well as offering a higher shock and impact resistance compared to OEM-style belts. Refreshing the rollers and/or tensioners simultaneously is a great way to ensure all vital components of your drive belt system are functioning optimally for years to come!
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    Hydraulic Alternator Belt Tensioner Roller - 11281748131
    10X Entries Into Our F80 M3 Sweepstakes
    Bremmen Parts - Corporate Logo
    T#:30629659
    Part#: 11281748131
    In Stock
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    This pulley is mounted along with the hydraulic belt tensioner but can be replaced on its own. It is used for the main drive belt on the M50-M54 family engines (M50, M50TU, M52, S52, M52TU, M54, M56, and S54 engines). This is the same belt that covers the water pump/alternator/power steering systems. Replacement is a very easy procedure (requires fan removal) and will have your engine purring in no time. Belt replacement is strongly recommended at the same time. If you have a mechanical belt tensioner, the pulley can only be replaced with a new tensioner.

    This high-quality replacement from Bremmen Parts is designed for exact fitment on your BMW. Whether you're looking to complete much-needed preventative maintenance, or replacing a failed roller, choose this component from Bremmen Parts for a lasting repair.

    If you need the hydraulic belt tensioner, click here.

    This item is 70mm Diameter. Please check the diameter before ordering.

    This tensioner pulley fits the following BMWs: 1991-1995 E34 525i (M50 engine) 1992-1999 E36 325i, 325is, 328i, 328is, 323is 1995-1999 E36 M3 (M3 3.0 & M3 3.2 liter) 1997-2003 E39 525i, 528i, 530i - Only for Hydraulic Tensioner 1999-2000 E46 323i, 323Ci, 328i, 328Ci - Only for Hydraulic Tensioner 2001-2005 E46 325i, 325Ci, 325xi, 330i, 330Ci, 330xi - Only for Hydraulic Tensioner 2001-2006 E46 M3 coupe & convertible - Only for Hydraulic Tensioner 2000-2006 X5 3.0 liter (E53 chassis) 2004 E60 525i, 530i (M54 engine) 1997-2002 Z3 & MZ3 2.5, 2.8, 3.0, M Roadster, M Coupe 2003-2009 Z4 M Coupe and Roadster

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    Idler Pulley
    10X Entries Into Our F80 M3 Sweepstakes
    Bremmen Parts - Corporate Logo
    T#:30629656
    Part#: 11287841228
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    Hex Bolt - N52, N54
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    Bavarian Autosport - Corporate Logo
    T#:19792190
    Part#: 11211439395
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    $ 15.19 USD
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    Replacement center bolt for the engine crank pulley.