MMX Billet Aluminium Expansion Tank Cap 60mm for BMW & MINI, Coolant Reservoir/Header Tank Lid, Fits OE 17 11 7 639 024

Premium billet aluminium expansion tank lid for BMW and MINI enthusiasts

Upgrade your engine bay with a precision-machined 60 mm reservoir top that looks smart and feels reassuring every time you twist it on. Designed and engineered in the UK from a solid billet of aluminium, this direct replacement radiator header tank lid delivers a high-quality finish and a secure, positive fit for long-lasting reliability on the road and on track.

Unlike stick-on dress-up covers, this is a full replacement part that swaps straight onto the factory expansion reservoir. The result is a tougher, better-looking cooling system lid that elevates your bay and inspires confidence.

• CNC-machined from solid aluminium for strength and durability
• Direct swap for the original reservoir top, no adapters or covers
• Crisp, precise engagement for a confident seal
• Ideal for engine bay styling, performance builds and daily drivers
• Engine cooling system upgrade with a premium motorsport look

Compatibility

Fits vehicles using OEM reference 17 11 7 639 024. If your Bavarian model or MINI Cooper variant shares this OE part number, this billet reservoir lid is the correct fit. Always check your existing expansion tank cap number before ordering.

Why choose this reservoir cap from us

• UK-engineered quality with an excellent fit and finish
• We use this part on our own builds and customer cars with great feedback
• Popular search terms: radiator reservoir cover, expansion tank cap, header tank lid, engine coolant reservoir top, billet alloy tank cap, BMW Mini water tank cap

Fitting service

Installation is straightforward. For professional fitting, choose MJ Modifications in Warwickshire. Request a quote: info@mjmodifications.co.uk.

Add this billet expansion reservoir lid to your basket today for a smarter, tougher and more satisfying finish to your BMW or MINI cooling system.