{"product_id":"1h0-121-687-a-genuine-vw-audi-coolant-expansion-tank-cap-seal","title":"1H0-121-687-A Genuine VW\/Audi Coolant Expansion Tank Cap Seal","description":"\u003ch2\u003eRenew the seal between the original coolant cap and reservoir\u003c\/h2\u003e\u003cp\u003e1H0-121-687-A is the Genuine VW\/Audi sealing ring for the specified coolant expansion-tank caps. Its nominal 28.5 × 3.8 mm dimensions must match the original serviceable cap and sealing arrangement.\u003c\/p\u003e\u003cp\u003eThe seal helps contain coolant at the cap-to-reservoir connection. The cap's pressure-regulating mechanism and the reservoir neck are separate parts of the system, so replacing the ring alone is appropriate only when those components remain serviceable.\u003c\/p\u003e\u003ch3\u003eTechnical details\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eComplete factory number: 1H0-121-687-A.\u003c\/li\u003e\n\u003cli\u003eFactory specification: nominal 28.5 × 3.8 mm expansion-tank cap sealing ring.\u003c\/li\u003e\n\u003cli\u003eDesign: black circular elastomer seal, as shown in the archive photograph.\u003c\/li\u003e\n\u003cli\u003eQuantity supplied: one individual cap seal.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eOne individual sealing ring is supplied. Expansion tank, pressure cap, coolant, hoses and other seals are separate. The nominal ring size is a functional part dimension and is not a packaged shipping measurement.\u003c\/p\u003e\u003ch3\u003eCommon reasons to replace\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eThe original seal is cracked, flattened or hardened.\u003c\/li\u003e\n\u003cli\u003eA leak is confirmed at the cap's sealing surface.\u003c\/li\u003e\n\u003cli\u003eThe ring is damaged during approved cap service.\u003c\/li\u003e\n\u003cli\u003eThe original ring is missing from a cap designed to use this service seal.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eInspect the reservoir neck and complete cap. Coolant residue can have several causes, including a damaged tank, an incorrect cap or a pressure-control fault. Diagnose the cooling system and replace a faulty cap assembly when required.\u003c\/p\u003e\u003ch3\u003eVehicle fitment\u003c\/h3\u003e\u003cp\u003eConfirmed cap-seal applications are listed below. Compare the installed cap, seal profile and complete factory number. A cap supersession or an aftermarket cap can use a different sealing arrangement.\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eVehicle\u003c\/th\u003e\n\u003cth\u003eModel years\u003c\/th\u003e\n\u003cth\u003eEngine\u003c\/th\u003e\n\u003cth\u003eConfiguration\u003c\/th\u003e\n\u003cth\u003eApplication restrictions\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolkswagen Cabrio\u003c\/td\u003e\n\u003ctd\u003e1995–2002\u003c\/td\u003e\n\u003ctd\u003e2.0L gasoline\u003c\/td\u003e\n\u003ctd\u003eConvertible; original matching reservoir cap\u003c\/td\u003e\n\u003ctd\u003eAssigned cap sealing ring only; confirm the installed cap's serviceable seal design.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolkswagen Passat\u003c\/td\u003e\n\u003ctd\u003e2000–2001\u003c\/td\u003e\n\u003ctd\u003e1.8L turbocharged gasoline or 2.8L gasoline\u003c\/td\u003e\n\u003ctd\u003eSedan or wagon; original matching reservoir cap\u003c\/td\u003e\n\u003ctd\u003eFactory reservoir-cap seal position; verify cap and original number.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolkswagen Golf SportWagen\u003c\/td\u003e\n\u003ctd\u003e2015\u003c\/td\u003e\n\u003ctd\u003e1.8L turbocharged gasoline or 2.0L TDI\u003c\/td\u003e\n\u003ctd\u003eWagon; original matching reservoir cap\u003c\/td\u003e\n\u003ctd\u003eAssigned cap seal; not a hose connector O-ring.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolkswagen GTI\u003c\/td\u003e\n\u003ctd\u003e2024\u003c\/td\u003e\n\u003ctd\u003e2.0L turbocharged gasoline\u003c\/td\u003e\n\u003ctd\u003eS hatchback; original matching reservoir cap\u003c\/td\u003e\n\u003ctd\u003eOriginal cap sealing-ring position; inspect cap and reservoir neck separately.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eInstallation guidance\u003c\/h3\u003e\u003cp\u003eAllow the cooling system to cool completely before following the prescribed pressure-release procedure. Remove the old ring without damaging the cap groove, clean the seat and install the new seal evenly. Use only any lubricant specifically required by the repair procedure.\u003c\/p\u003e\u003cp\u003eCheck cap installation and perform the required cooling-system leak or pressure test. Verify coolant level and inspect the serviced area after normal temperature cycling.\u003c\/p\u003e\u003ch3\u003eOrdering information\u003c\/h3\u003e\u003cp\u003eOne individual Genuine VW\/Audi 1H0-121-687-A coolant expansion-tank cap seal, nominal 28.5 × 3.8 mm. Cap, reservoir and coolant are sold separately.\u003c\/p\u003e","brand":"Genuine VW\/Audi","offers":[{"title":"Default Title","offer_id":48048302948529,"sku":"1H0-121-687-A","price":6.77,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0681\/1379\/3201\/files\/1h0-121-687-a-genuine-vw-audi-1.jpg?v=1792146857","url":"https:\/\/hstuning.com\/products\/1h0-121-687-a-genuine-vw-audi-coolant-expansion-tank-cap-seal","provider":"HS Tuning ","version":"1.0","type":"link"}