{"product_id":"mmx-bmw-mini-60mm-billet-coolant-expansion-cap","title":"MMX BMW \u0026 MINI 60mm Billet Coolant Expansion Tank Cap","description":"\u003cp\u003eThe \u003cstrong\u003eMMX 60mm Billet Coolant Expansion Cap\u003c\/strong\u003e is designed from the ground up in the UK and engineered from a solid billet of aluminium as a direct replacement for the factory coolant cap. It fits BMW and MINI models running \u003cstrong\u003eOE part number 17 11 7 639 024\u003c\/strong\u003e, and replaces that cap outright rather than covering it.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eMatch The Cap Diameter, Not The Model\u003c\/h3\u003e\n\u003cp\u003eBMW uses two common expansion tank cap sizes across its modern range, 60mm and 90mm, and they are not interchangeable. The number on the factory cap is the definitive check: this MMX cap replaces OE 17 11 7 639 024. Models running the larger 90mm cap are covered by a separate MMX part.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003ePressure Retained, Finish Improved\u003c\/h3\u003e\n\u003cp\u003eA coolant cap is a pressure component, not a trim item, which is why MMX builds a full replacement instead of a cosmetic cover. The billet cap retains the correct system pressure and seal while removing the faded, brittle plastic that lets down an otherwise tidy engine bay.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eCNC-machined in the UK from solid billet aluminium\u003c\/li\u003e\n\u003cli\u003eDirect replacement for OE part number 17 11 7 639 024\u003c\/li\u003e\n\u003cli\u003e60mm expansion tank fitment\u003c\/li\u003e\n\u003cli\u003eNot an adhesive cover – the factory cap is replaced outright\u003c\/li\u003e\n\u003cli\u003eAnodised finish for lasting corrosion resistance\u003c\/li\u003e\n\u003cli\u003eFully reversible – the OEM cap can be refitted at any time\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e MMR03-1503\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplaces OE:\u003c\/strong\u003e 17 11 7 639 024\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiameter:\u003c\/strong\u003e 60mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Billet aluminium, anodised\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBMW and MINI models fitted with the 60mm expansion tank cap, OE 17 11 7 639 024\u003c\/li\u003e\n\u003cli\u003eAlways confirm the part number on the existing cap before ordering\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHow is 60mm confirmed against 90mm?\u003c\/strong\u003e\u003cbr\u003eRead the part number on the factory cap. 17 11 7 639 024 is the 60mm cap; 17 11 7 639 021 is the 90mm version, for which MMX offers a separate part.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan the cap be fitted with the engine hot?\u003c\/strong\u003e\u003cbr\u003eNo. A cooling system should only be opened when fully cold, exactly as with the factory cap.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eWhy Choose An MMX Billet Cap?\u003c\/h3\u003e\n\u003cp\u003eCoolant caps sit in the most visible part of the engine bay and are the first component to look tired. MMX machines a full-function replacement that holds pressure properly and looks right for years. R44 Performance stocks the complete MMX under-bonnet range.\u003c\/p\u003e","brand":"MMX","offers":[{"title":"Default Title","offer_id":57929981559166,"sku":"MMR03-1503","price":98.27,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0280\/7568\/8011\/files\/MMR03-1503_1bf09ff2-270b-4dd5-a7e2-374bd939653e.png?v=1787916850","url":"https:\/\/r44performance.com\/products\/mmx-bmw-mini-60mm-billet-coolant-expansion-cap","provider":"R44 Performance","version":"1.0","type":"link"}