BDFHYK Engine Coolant Expansion Reservoir for Nissan Altima/Maxima (2002-2006) - OE Fit, Polypropylene Overflow Tank

BDFHYK replacement coolant expansion reservoir is a direct-fit overflow tank engineered to replace OE 21710-8J000 for Nissan Altima (2002–2006) and Maxima (2004–2006), restoring proper coolant level access and overflow control.

This replacement overflow tank is molded from high-quality polypropylene to match the original equipment form and function. It provides visible coolant level monitoring without removing the radiator cap, helps relieve pressure in the cooling circuit, and offers OE-grade durability for daily driving. The part cross-references include 21710-8J000, NI3014105, and 603-614 to help confirm compatibility before purchase.

How do I know this reservoir fits my Nissan?

Verify fit by matching your vehicle year, engine size, and OE number. This tank covers Nissan Altima 2002–2006 with 2.5L and 3.5L engines and Nissan Maxima 2004–2006 3.5L V6, and lists OE references to simplify checks.

• Compatible models: Altima 2002–2006 (2.5L and 3.5L), Maxima 2004–2006 (3.5L).
• OE cross-reference: 21710-8J000, NI3014105, 603-614.
• Confirm by comparing the old tank shape, mounting points, and inlet/outlet locations.
• Check the product images or vehicle fitment tool for verification.

What are the main material and performance benefits?

The tank is manufactured from durable polypropylene (PP), chosen for chemical resistance and long-term heat tolerance. Its construction resists cracking and deformation from normal engine bay temperatures and coolant exposure while allowing you to inspect fluid level visually.

• PP construction resists corrosion and coolant chemicals.
• Transparent sections for quick visual level checks.
• Designed to withstand typical under-hood thermal cycles.
• OE-grade durability for a reliable replacement lifecycle.

How does installation and maintenance work?

Installation is straightforward for anyone comfortable with basic under-hood work; the part includes instructions to guide you. Remove the old tank, transfer any sensors or hoses, and secure the new reservoir to the existing brackets and fittings.

• Includes written installation guidance in the package.
• Reuses original mounting points and hose connections where applicable.
• Inspect hose clamps and hoses for wear and replace if necessary.
• No radiator cap removal required to check coolant level with this tank.

Will this affect cooling system operation or emissions?

This reservoir is a passive component designed to manage overflow and provide visual level information; it does not change cooling system dynamics or emissions by itself. Installing a properly fitting, undamaged tank helps the cooling system operate as intended and reduces the risk of coolant loss or air ingress that could lead to overheating.

• Maintains overflow capacity to prevent coolant loss under pressure.
• Helps avoid air pockets that can impair circulation.
• Proper fit reduces the chance of leaks from poor sealing or cracked tanks.

Who is this for: Drivers and DIY mechanics who own a Nissan Altima (2002–2006) or Maxima (2004–2006) and need a reliable OE-style replacement overflow tank. It’s ideal for those replacing a cracked, discolored, or leaking reservoir, or anyone restoring original coolant system functionality with a part that matches factory form and fit. BDFHYK provides industrial manufacturing quality, installation instructions in the box, and customer support to help confirm fitment or resolve issues within 48 hours.