Moroso Coolant Expansion Tank | 2003-2012 Mazda RX-8 (63814)

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2003-2012 Mazda RX-8 Coolant Expansion Tank by Moroso

The factory coolant tank in the RX-8 is known to fail after repeated high-heat situations. The neck may become deformed, or the tank may separate completely. This replacement tank by Moroso is constructed from high quality aluminum and features a billet aluminum radiator neck that accepts OEM small radiator caps. This coolant expansion tank is a direct bolt-in replacement for the flimsy stock plastic tank. The superior craftsmanship and quality materials guarantee that this product outperforms the OEM piece in every single way.


  • Direct bolt-in replacement to stock plastic tank
  • Fabricated Aluminum for strength and durability
  • Features a billet aluminum radiator neck that accepts O.E.M. Small radiator caps (SAE Type B/43mm)
  • This Aluminum tank can be polished, chromed, painted, powder coated or left as is for a race look


  • 2003 - 2012 Mazda RX-8

What's In The Box?

  • 1 - Coolant Expansion Tank



Moroso Manufacturer's Warranty

Customer Reviews

Based on 6 reviews
Daviel Aldama-Sanchez
Great product, recommended

It’s a great replacement has no issue

Get it!!

Lester Kelley
Beautiful Upgrade

Excellent replacement for the junky old OEM one. Plus it dresses up the engine bay a bit.

Nicklas Ng

nice fitment, hope it last long indeed

Marco Cirone
Coolant tank

Very nice product

excellent replacement for puny OEM tank

This is a nice direct-fit replacement for the failure-prone OEM plastic tank (WHY do these guys make ANY cooling system part plastic? Oh, yeah...designed obsolence...). Anyway, you DO lose the low coolant sensor so Moroso would be wise to include this in the future...I mean would add about 29 cents to the cost and complexity...just do it.