When coolant expansion tank performance matters, the SWAG 30 10 3446 delivers — built to the same dimensional and material standards as the original part it replaces. The part is built to the following specification: for OE number: 5Q0 121 407 M, Weight [kg]: 0, 38 kg, Material: 24, Supplementary Article/Supplementary Info: 896, Number of connectors: Aluminium. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Compatible with AUDI, CUPRA, SEAT, SKODA and 1 other makes vehicles; use the vehicle selector above to confirm exact fitment for your make, model, and engine variant. Fitment data is sourced from TecDoc, the authoritative European parts catalogue. This part supersedes original equipment references: 001-10-25044, 00273001, 003-026-006, .005.4541 and 113 more. Matching these numbers confirms a like-for-like replacement with no loss of function. SWAG is a recognised supplier of automotive replacement components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched with tracked delivery and a 14-day money-back guarantee with hassle-free returns.

SWAG, part of the bilstein group based in Ennepetal, Germany, is a trusted independent aftermarket brand offering a wide range of quality replacement parts. SWAG specialises in engine components, suspension parts, steering elements, cooling system parts, and rubber-to-metal components. Manufactured to OE-equivalent standards with IATF 16949 certification, SWAG products deliver dependable performance at a competitive price point. As a sister brand to febi bilstein, SWAG benefits from shared German engineering expertise and rigorous quality control processes.