Genuine Mazda Coolant Expansion Tank / Sub-Radiator Tank • LFG1-15-350C

Genuine Mazda LFG1-15-350C Coolant Expansion Tank / Sub-Radiator Tank

Replacement Genuine Mazda coolant expansion tank / sub-radiator tank for Mazda MX-5 Mk3, Mk3.5 and Mk3.75 / NC 1.8-litre and 2.0-litre petrol models listed in the compatibility table.

The expansion tank forms part of the pressurised engine cooling system. It provides space for the coolant to expand as the engine warms up and allows coolant to return to the system as it cools, helping maintain the correct coolant level and system pressure.

The tank is mounted within the engine bay and connects to the surrounding cooling system through its hose outlets. There is one expansion tank fitted per vehicle. This listing supplies one Genuine Mazda coolant expansion tank.

Replacement may be required where the original plastic tank has become brittle, discoloured, cracked or distorted. Typical symptoms include visible coolant staining, dampness around the tank seams or hose connections, gradual coolant loss, difficulty maintaining cooling-system pressure or overheating caused by coolant escaping from a damaged reservoir.

• Part type: Coolant expansion tank / sub-radiator tank
• Primary use: Allows coolant expansion and return within the pressurised cooling system
• Location: Engine bay
• Position: Engine cooling system
• Quantity per vehicle: 1
• Quantity supplied: 1 coolant expansion tank
• Brand: Genuine Mazda
• Part No.: LFG1-15-350C
• Also referenced as: LFG115350C
• Supersedes: LFG1-15-350A and LFG1-15-350B
• Fitment note: Suitable for the Mazda MX-5 NC 1.8-litre and 2.0-litre petrol applications listed in the compatibility table

Fitment advice: Inspect the coolant hoses, hose clips, pressure cap and mounting points while the original tank is removed. The hose connections should be clean and free from damage before installation. For imported, modified, engine-swapped or previously repaired cars, matching the original tank design, hose arrangement and part number is recommended.

Other items to consider: When changing this part, you may also want to consider purchasing a replacement pressure cap, associated coolant hoses, new hose clips and fresh Mazda-compatible coolant.

Useful tools / consumables: Socket set, hose-clip pliers, coolant drain container, funnel or vacuum-filling tool, cleaning materials and the correct Mazda-compatible coolant mixture.

Difficulty guide: DIY Difficulty: Moderate. The engine must be completely cool before the pressurised cooling system is opened. Coolant may need to be drained, the connected hoses removed carefully and the system refilled and bled correctly after installation.

Why Genuine Mazda? Genuine Mazda cooling components are designed to match the original tank capacity, material specification, mounting points, hose alignment and pressure-cap seating arrangement. Correct dimensional accuracy helps maintain reliable coolant containment, pressure control and compatibility with the surrounding cooling system.

What’s in the box: One Genuine Mazda coolant expansion tank / sub-radiator tank.

Installation notes: Allow the engine to cool fully before opening the cooling system. Drain the coolant to a suitable level, disconnect the hoses without damaging their ends and transfer any reusable fittings required for installation. Secure the replacement tank correctly, reconnect the hoses and clips, refill with the specified coolant mixture and bleed trapped air from the system. Bring the engine to operating temperature and inspect the tank seams, cap seating area and hose connections carefully for leakage.