{"product_id":"n-900-351-03-genuine-vw-audi-coolant-pipe-o-ring","title":"N-900-351-03 Genuine VW\/Audi Coolant Pipe O-Ring","description":"\u003ch2\u003eGenuine O-ring for the specified coolant pipe union\u003c\/h2\u003e\u003cp\u003eN-900-351-03 is the Genuine VW\/Audi O-ring used to seal the original coolant pipe union on the applications below. The nominal factory specification is 21×3.\u003c\/p\u003e\u003cp\u003eThe seal closes the assigned pipe connection while the surrounding hardware retains the fitting. Cooling systems contain many O-rings of similar appearance, so match the complete factory number and original connection before ordering.\u003c\/p\u003e\u003ch3\u003eTechnical details\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eComplete factory number: N-900-351-03.\u003c\/li\u003e\n\u003cli\u003eFactory specification: 21 mm nominal inside diameter × 3 mm cross-section.\u003c\/li\u003e\n\u003cli\u003eDesign: round-section coolant pipe O-ring.\u003c\/li\u003e\n\u003cli\u003eQuantity supplied: one individual O-ring.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eThe bore and cross-section are functional component dimensions. They do not make this seal a universal replacement for another cooling-system joint. Material composition and packaged shipping dimensions are not specified here.\u003c\/p\u003e\u003ch3\u003eCommon reasons to replace\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eCoolant seepage is traced to this sealed connection.\u003c\/li\u003e\n\u003cli\u003eThe original ring is flattened or has lost elasticity.\u003c\/li\u003e\n\u003cli\u003eThe ring is cut, cracked or pinched.\u003c\/li\u003e\n\u003cli\u003eThe fitting has been removed for service.\u003c\/li\u003e\n\u003cli\u003eAn incorrect seal was installed during a previous repair.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eInspect the pipe union, receiving bore and sealing surfaces for corrosion, cracking or damage. A new O-ring cannot correct a cracked fitting or damaged sealing surface. Identify the source of a leak before replacing parts.\u003c\/p\u003e\u003ch3\u003eVehicle fitment\u003c\/h3\u003e\u003cp\u003eUse only at the original coolant pipe union assigned N90035103. This seal is separate from the coolant pump perimeter seal and other O-rings in the same system.\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\u003eAudi 4000 quattro\u003c\/td\u003e\n\u003ctd\u003e1985\u003c\/td\u003e\n\u003ctd\u003e2.2L gasoline I5\u003c\/td\u003e\n\u003ctd\u003eSedan; quattro; Original coolant pipe union seal\u003c\/td\u003e\n\u003ctd\u003eOriginal coolant pipe union assigned N90035103, nominal 21×3. Confirm the actual connection.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAudi Coupe GT\u003c\/td\u003e\n\u003ctd\u003e1984\u003c\/td\u003e\n\u003ctd\u003e2.2L gasoline I5\u003c\/td\u003e\n\u003ctd\u003eCoupe; Original coolant pipe union seal\u003c\/td\u003e\n\u003ctd\u003eOriginal coolant pipe union assigned N90035103, nominal 21×3. Confirm the actual connection.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAudi quattro\u003c\/td\u003e\n\u003ctd\u003e1983, 1985\u003c\/td\u003e\n\u003ctd\u003e2.1L turbocharged gasoline I5\u003c\/td\u003e\n\u003ctd\u003eOriginal quattro coupe; Original coolant pipe union seal\u003c\/td\u003e\n\u003ctd\u003eOriginal coolant pipe union assigned N90035103, nominal 21×3. Confirm the actual connection.\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 and follow the factory draining and depressurizing procedure. Clean the sealing surfaces without damaging them, fit the correct seal without twisting it and use only the installation lubricant specified for the connection.\u003c\/p\u003e\u003cp\u003eRefill and bleed the cooling system according to the vehicle-specific procedure, then check the serviced joint for leaks and verify the coolant level after the required cooling cycle.\u003c\/p\u003e\u003ch3\u003eOrdering information\u003c\/h3\u003e\u003cp\u003eOne genuine O-ring is supplied. The pipe union, retaining hardware, hoses and coolant are not included. Confirm the original number and quantity needed.\u003c\/p\u003e","brand":"Genuine VW\/Audi","offers":[{"title":"Default Title","offer_id":48047256010929,"sku":"N-900-351-03","price":5.13,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0681\/1379\/3201\/files\/n-900-351-03-genuine-vw-audi-1.jpg?v=1792133903","url":"https:\/\/hstuning.com\/products\/n-900-351-03-genuine-vw-audi-coolant-pipe-o-ring","provider":"HS Tuning ","version":"1.0","type":"link"}