A-Premium Power Steering Reservoir Tank with Cap for BMW (Direct-Fit, OE-Style)

A-Premium Power Steering Reservoir/Tank with Cap is a direct-fit replacement reservoir designed to restore proper power steering fluid containment and routing on compatible BMW vehicles.

This replacement reservoir is built to match original equipment dimensions and mounting points so installation is straightforward. Constructed from durable materials and supplied with a matching cap, the unit replaces worn, cracked, or leaking tanks that can cause fluid loss, noisy steering, or reduced steering assist. Below you will find clear answers to common buyer questions, plus specific fitment details so you can confirm compatibility with your BMW.

Which BMWs will this reservoir fit?

The A-Premium reservoir covers a wide range of BMW models and model years, including many 1-, 3-, and X-series vehicles across multiple engine sizes. Fitment includes both L4 and V8 variants where specified, and notes whether Active Steering is required or excluded. Always cross-check reference numbers or part numbers before purchase.

• Compatible models: 125i, 128i, 130i, 135i/135is; 323i, 325i, 328i, 330i, 335i/335d and many xDrive/X1/X3 variants.
• Years covered: ranges from 2006 through 2015 depending on the model and engine.
• Active Steering: some listings exclude vehicles with Active Steering—verify for your VIN.

How does this compare to the original equipment part?

This reservoir is engineered to match OEM form, fit, and function so it installs like the factory unit. Materials and mounting locations are designed to provide a secure fit and correct fluid routing, minimizing installation adjustments. The product also carries common reference numbers for easy cross-reference to original parts.

• Reference numbers: 603-979, 603979, PSR0032, 3R502, 32416851218, 32416768094.
• Includes matching cap for a complete assembly replacement.
• Manufactured for professional replacement with OE-style performance.

What are the practical benefits of replacing a failing reservoir?

Replacing a cracked or leaking reservoir prevents power steering fluid loss and contamination, restoring proper steering assist and reducing noise from the pump. Fresh, sealed components help maintain system pressure and extend the life of related components like hoses and the steering pump. Timely replacement lowers the risk of sudden steering issues while driving.

• Stops leaks that can cause low-fluid warnings or steering noise.
• Prevents air ingestion and contamination of steering fluid.
• Protects pump and hoses from premature wear due to fluid loss.

How reliable is the part and what warranty is included?

A-Premium offers a one-year unlimited-mileage guarantee on this power steering reservoir, backing workmanship and materials. The warranty provides added confidence for DIY installers and professional shops alike. Keep your purchase documentation to make any warranty claim straightforward.

• One-year unlimited-mileage coverage from A-Premium.
• Sold as a complete reservoir and cap assembly for ease of replacement.
• Intended as a professional replacement part with OE-style fit.

Who is this for: This A-Premium reservoir is intended for BMW owners, mechanics, and repair shops replacing an aging, cracked, or leaking power steering tank on compatible 1-, 3-, and X-series vehicles. If your BMW shows low steering fluid, visible reservoir damage, or steering pump noise, this direct-fit replacement is a practical, warranty-backed option to restore proper system operation.