How to drain and clean the Coolant Reservoir on Mazda 6?

Drain the cooling system. On all except 2012 and later 2.5L models, remove the fasteners securing the coolant reservoir to the fender. On 2012 and later 2.5L models, remove the fasteners that secure the reservoir to the fan shroud. Lift the reservoir up enough to disconnect the hoses. Clean out the reservoir with soapy water and a brush to remove any deposits inside. Inspect the reservoir carefully for cracks. If you find a crack, replace the reservoir. Installation is the reverse of removal.

Genuine Mazda 6 Coolant Reservoir

Coolant Tank Reservoir

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7 Coolant Reservoirs found

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Mazda 6 Reservoir Part Number: PYG6-15-351
$28.49 MSRP: $37.99
You Save: $9.50 (26%)
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Product Specifications
- Other Name: Tank, Sub-Radiator; Expansion Tank, Reservoir
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2018-2021 Mazda 6 | Carbon Edition, Grand Touring, Grand Touring Reserve, Signature | 4 Cyl 2.5 L GAS
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Mazda 6 Reservoir Part Number: PE01-15-351A
$30.04 MSRP: $40.07
You Save: $10.03 (26%)
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Product Specifications
- Other Name: Tank, Sub-Radiator; Reservoir, Reservoir Tank
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2014-2021 Mazda 6 | Grand Touring, Sport, Touring | 4 Cyl 2.5 L GAS
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Mazda 6 Reservoir Part Number: L518-15-350A
$31.49 MSRP: $41.99
You Save: $10.50 (26%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Tank, Sub-Radiator; Reservoir
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2009-2013 Mazda 6 | i, S | 4 Cyl 2.5 L GAS, 6 Cyl 3.7 L GAS
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Mazda 6 Reservoir Part Number: AJ57-15-350D
Product Specifications
- Other Name: Tank, Sub-Radiator
- Replaces: AJ57-15-350B, AJ57-15-350E, AJ57-15-350C
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2003-2008 Mazda 6 | S | 6 Cyl 3.0 L GAS
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Mazda 6 Reservoir Part Number: L321-15-350
Product Specifications
- Other Name: Tank, Sub-Radiator
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2003-2008 Mazda 6 | i | 4 Cyl 2.3 L GAS
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Mazda 6 Reservoir Part Number: L3K9-15-351B
Product Specifications
- Other Name: Tank, Sub-Radiator
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2006-2007 Mazda 6 | Mazdaspeed | 4 Cyl 2.3 L GAS
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Mazda 6 Reservoir Part Number: L5A3-15-351A
Product Specifications
- Other Name: Tank, Sub-Radiator; Reservoir
- Warranty: This genuine part is guaranteed by Mazda's factory warranty.
Fits the following Vehicles:
- 2011-2013 Mazda 6 | i | 4 Cyl 2.5 L GAS

Mazda 6 Coolant Reservoir

The Mazda 6 Coolant Reservoir maintains engine temperature by storing additional antifreeze until it is required once again, eliminating spills, rust and air bubbles that can cause harm to important components. This Coolant Reservoir is mounted next to the radiator and is connected with a hose that pulls expanding fluid in during heat and expels it during cooling when it pulls a vacuum to keep the radiator filled. Over the years, two primary designs have been applied by Mazda. In older and simpler overflow systems the pressure cap is mounted on the radiator itself, and the reservoir is not pressurized, just having a light plastic top. When the pressure is above the cap rating, the coolant is forced out, and when the temperature decreases, the cap has an embedded valve that allows the liquid to reenter. Subsequent Mazda 6s changed to an expansion type where the pressure cap was mounted directly on the tank, and the reservoir was a closed section of the pressurized circuit. Since it can hold full system pressure, the container is made of reinforced plastic which is thicker and is mounted higher than the radiator to allow trapped air to vent in an uninjurious manner. The pressurized expansion tank has faster self-bleeding and greater resistance to leaks compared to the other variant that performs the same job. Regardless of the version, distinct level marks carved into every Coolant Reservoir allow the driver to check the amount of coolant when the engine is cold so that their Mazda 6 remains running cool and clean.

Looking for Coolant Reservoir with proven quality? Choose OEM Coolant Reservoir. Mazda designs and builds them to strict factory specs. Every piece goes through rigorous quality checks. You'll get parts that fit right and work like new. Shop our huge inventory of OEM Mazda 6 parts. Enjoy the highly competitive prices online. Our site is your one-stop shop. Each genuine 6 part includes a manufacturer's warranty. Buy with confidence. Our return policy is simple and hassle-free. In a rush? Choose expedited delivery at checkout. You'll love the streamlined experience from search to checkout to receiving your order.

Mazda 6 Coolant Reservoir Parts and Q&A

Reservoir
L518-15-350A
Q: How to drain and clean the Coolant Reservoir on Mazda 6?
A:
Drain the cooling system. On all except 2012 and later 2.5L models, remove the fasteners securing the coolant reservoir to the fender. On 2012 and later 2.5L models, remove the fasteners that secure the reservoir to the fan shroud. Lift the reservoir up enough to disconnect the hoses. Clean out the reservoir with soapy water and a brush to remove any deposits inside. Inspect the reservoir carefully for cracks. If you find a crack, replace the reservoir. Installation is the reverse of removal.