{"product_id":"x-autohaux-coolant-radiator-reservoir-tank-5q0121407a-for-audi-a3-2012-2020-direct-fit-with-cap-2-pin-sensor","title":"X AUTOHAUX Coolant Radiator Reservoir Tank 5Q0121407A for Audi A3 2012–2020 — Direct‑Fit with Cap \u0026 2‑Pin Sensor","description":"\u003cp\u003e\u003cstrong\u003eX AUTOHAUX Coolant Radiator Reservoir Tank 5Q0121407A is a direct-fit replacement overflow expansion bottle with cap and 2-pin sensor designed for Audi and select VW\/Seat models, restoring proper coolant containment and level monitoring.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eIf your vehicle shows coolant loss, a low-level warning, or you spot cracks or discoloration in the old reservoir, replacing it with a correct, high-quality tank prevents leaks and maintains engine cooling performance. This X AUTOHAUX assembly corresponds to part numbers 5Q0121407A\/D\/G and arrives complete with the threaded cap and the 2-pin level sensor so you can swap the unit without sourcing additional components.\u003c\/p\u003e\n\n\u003ch3\u003eWill this reservoir fit my car?\u003c\/h3\u003e\n\u003cp\u003eThis reservoir is manufactured to match original equipment fitment for many MQB-platform vehicles. It fits Audi A3 (8VA, 8VF) 2012–2020 and many related models listed below, so verify your vehicle's part number and year before ordering.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatible models include Audi A3 (8VA\/8VF) 2012–2020, Audi Q2 (GAB) 2016–2020, Audi Q3 (F3) 2018–2020, Audi TT Mk3 (FV) 2014–2020.\u003c\/li\u003e\n  \u003cli\u003eAlso fits Volkswagen Arteon (3H7) 2017–2020, VW Golf Mk7 2012–2020, Volkswagen Passat (3G) 2014–2020, Seat Ateca (KH) 2016–2020.\u003c\/li\u003e\n  \u003cli\u003eConfirm compatibility by matching your existing reservoir part number (5Q0121407A\/D\/G) or consulting your VIN-based parts lookup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does it restore cooling system reliability?\u003c\/h3\u003e\n\u003cp\u003eReplacing a cracked or deteriorated reservoir stops coolant leaks and restores proper expansion volume for temperature changes. The included 2-pin sensor sends accurate level information to your vehicle’s warning system, helping you avoid undetected coolant loss.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRestores sealed coolant expansion capacity to reduce overflow and spillage.\u003c\/li\u003e\n  \u003cli\u003eReplaces faulty or brittle plastic that can deform or crack with age and heat exposure.\u003c\/li\u003e\n  \u003cli\u003eReinstates the coolant level sensor for correct dashboard warnings.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat are the materials and build quality like?\u003c\/h3\u003e\n\u003cp\u003eThe tank is made from durable, automotive-grade plastic engineered to resist rust, oxidation, and deformation under normal operating conditions. Molded mounting points and hose connections match OE dimensions to ensure a secure fit and long service life when installed properly.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDurable construction resists fluid loss and heat-related deformation.\u003c\/li\u003e\n  \u003cli\u003eOE-style mounting and hose fittings reduce installation adjustment.\u003c\/li\u003e\n  \u003cli\u003eSupplied cap and sensor included to eliminate extra sourcing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow difficult is installation and what should I prepare?\u003c\/h3\u003e\n\u003cp\u003eInstallation is straightforward for anyone with basic mechanic skills and common tools. Work on a cold engine, catch the coolant, swap the old tank for the new unit, reconnect hoses and wiring, and top up coolant to the correct level.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAllow engine to cool fully before starting work to avoid burns.\u003c\/li\u003e\n  \u003cli\u003eDrain remaining coolant into a pan, unbolt the old reservoir, and transfer hoses carefully.\u003c\/li\u003e\n  \u003cli\u003eReinstall the new tank, tighten clamps, reconnect the 2-pin sensor, refill coolant, and test for leaks.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: This X AUTOHAUX reservoir tank is intended for owners, DIY mechanics, and independent repair shops working on MQB-based Audis, Volkswagens, and Seats that require part numbers 5Q0121407A\/D\/G. It’s ideal for vehicles showing coolant level warnings, visible reservoir damage, or when performing a thorough cooling-system refresh. Always confirm fitment against your vehicle’s part number or VIN before purchase and dispose of drained coolant responsibly.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does this reservoir include the cap and sensor?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes — the unit ships complete with the threaded cap and the 2-pin coolant level sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I install it myself?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes, with basic tools and a cool engine; drain coolant, swap the tank, reconnect hoses and sensor, then refill.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"X AUTOHAUX","offers":[{"title":"Default Title","offer_id":48085626486942,"sku":"B0C53PSN48","price":41.59,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/x-autoHaux-front-view-reservoir-tank.jpg?v=1785875246","url":"https:\/\/northtrailauto.ca\/products\/x-autohaux-coolant-radiator-reservoir-tank-5q0121407a-for-audi-a3-2012-2020-direct-fit-with-cap-2-pin-sensor","provider":"North Trail Auto","version":"1.0","type":"link"}