Coolant Expansion Tank for MG 3/MGTF

This tank is engineered for MG 3 models from 2011–2023, so your 2020 MG 3 is fully compatible. However, we also stock a 2024 MG 3 variant for newer model years. If you're unsure which generation your vehicle is, contact us with your VIN and we'll confirm the correct SKU for your specific model.

We offer three SKU variants to match your specific MG model: Old MG 3 (2011–2023 standard MG 3), New MG 3SW Sub Coolant Tank (for the MG 3SW subcompact variant), and MGTF (for the MGTF roadster). Each is engineered as a 1:1 direct replacement with perfectly aligned mounting points and hose connectors for your vehicle. Select the SKU that matches your exact model to ensure proper fitment and plug-and-play installation.

This is a DIY-friendly replacement if you're comfortable working with cooling systems. The installation involves disconnecting the sensor, draining the old tank, removing hoses and mounting bolts, and installing the new tank with reconnection of hoses and the sensor. The most important step is ensuring the engine is completely cold before you begin—opening a hot cooling system can cause severe burns from pressurized steam. If you're not confident working with your vehicle's cooling system, we recommend having a professional technician perform the installation.

The tank is constructed from premium UV-stabilized PA66/PP plastic reinforced to withstand extreme thermal cycles without warping or cracking. The ultrasonic-welded construction creates a superior bond capable of handling high-pressure cooling systems and preventing seam leaks. The internal structure also resists modern OAT coolants, preventing chemical degradation and extending service life well beyond standard generic tanks.

This tank features high-translucency wall construction that allows you to easily see the coolant color and level at a glance without opening the cap. Additionally, the integrated sensor port connects to your vehicle's factory coolant level sensor, so your dashboard warning system will alert you if the level drops too low. This dual visibility ensures you never run low on vital coolant.

The package includes one coolant expansion tank with cover. You'll need to supply your own MG-approved coolant for topping up during installation, and you may need a siphon pump or drain pan if you don't already have one. All hoses, clamps, and the sensor connector from your old tank will be reused with the new unit.

After you've reconnected all hoses and the sensor, fill the new tank to the MAX line with recommended coolant, then start the engine with the cap off. Allow the engine to reach operating temperature until the thermostat opens, massage the hoses to remove air pockets, top up as needed, and finally tighten the pressure cap. This bleeding process typically takes 15–20 minutes depending on how much air is trapped in the system. Rest assured that taking time to properly bleed the cooling system prevents future overheating issues.

Use the vehicle selector at the top of this page to confirm fitment for your specific year, brand, and model. If your vehicle is not listed or you're unsure, contact us at support@evparts4x4.com with your VIN — we'll confirm compatibility within 24 hours. Our Guaranteed Fit policy means if a compatibility issue is on our end, we'll make it right.

Orders are processed and dispatched within 2-4 business days. Standard parts ship via Air Parcel and typically arrive in 10-15 business days; larger body parts ship via Sea Freight and take around 30-45 business days. Shipping is free on orders over $100. You'll receive a tracking number once your order ships, and can track it anytime here. Full details in our Shipping Policy.

Yes — we offer a 30-day return window from the delivery date, and we don't charge any restocking fees. If an item arrives damaged or isn't quite right on our end, we'll arrange a replacement or full refund and cover the return shipping. For the complete terms, please see our Return & Refund Policy or start a return via our RMA page.

We don't provide installation directly, but most of our parts are designed for straightforward DIY installation — the step-by-step guide is in the Installation Guide tab above. For complex parts (e.g. brakes, suspension, electrical systems), we recommend having a qualified mechanic perform the installation. If you have technical questions during installation, our support team is happy to help at support@evparts4x4.com.