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
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Turner Motorsport - Corporate Logo
T#:15876877
Part#: 049453LA01-02
In Stock
Sale - Save 25% $ 132.99

This product was last offered at the strikethrough price on
06-14-2026

$ 99.99 USD
Free Shipping on orders $49 and up
Sale - Save 25%
$ 132.99

This product was last offered at the strikethrough price on
06-14-2026

$ 99.99 USD
Free Shipping on orders $49 and up

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 Power Pulley Upgrade Kit - Z4 M Roadster & Coupe ...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Turner Motorsport - Corporate Logo
T#:3465
Part#: PPK-MZ4
Back Ordered
Sale - Save 25% $ 354.99

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

$ 266.24 USD
Free Shipping
Sale - Save 25%
$ 354.99

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

$ 266.24 USD
Free Shipping
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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