Aluminum Coolant Overflow Expansion Tank for Infiniti Q50 (2016-2021) 3.0L

TIG-Welded Aluminum Coolant Overflow Expansion Tank for 2016-2021 Infiniti Q50 (V37)

What it Does: The Aluminum Coolant Overflow Expansion Tank replaces the failure-prone factory dual-chamber plastic reservoir on the 2016-2021 Infiniti Q50 to eliminate seam separation and maintain cooling system pressure integrity under high thermal loads.

The Stock Infiniti Q50 Coolant Reservoir Failure Point

On the V37 platform, the factory expansion tank is tasked with managing both the engine cooling loop and the secondary air-to-water intercooler circuit. Prolonged heat cycling from the twin-turbo VR30DDTT quickly degrades the OEM PA66 plastic, causing it to yellow, embrittle, and warp. Sustained cooling pressures lead to micro-fractures along the sonic-welded plastic seams, stripped pressure cap necks, and weeping hose barbs. Under tuned conditions with increased boost and underhood temperatures, these plastic tanks frequently crack, causing pressure loss, boiling coolant, and catastrophic overheating.

The Engineering Solution

Constructed from lightweight, high-strength AA5052 aluminum alloy, this dual-chamber expansion tank serves as a permanent replacement for problematic OEM plastic. Every joint, baffle, and hose barb is precision TIG-welded to prevent stress fractures and endure continuous pressure without flexing or ballooning. The dual-reservoir design preserves separate volumes for the engine and charge-air circuits while utilizing factory mounting tabs and OEM hose geometry for clean integration. Each tank undergoes pneumatic leak testing to guarantee zero seam failure, ensuring complete reliability over the lifespan of OEM part number 21710-5CF0A.

Technical Specifications

Compatibility

• 2016-2021 Infiniti Q50 3.0t Luxe (VR30DDTT)
• 2016-2021 Infiniti Q50 3.0t Premium (VR30DDTT)
• 2016-2021 Infiniti Q50 3.0t Sport (VR30DDTT)
• 2016-2021 Infiniti Q50 3.0t Signature Edition (VR30DDTT)
• 2016-2021 Infiniti Q50 Red Sport 400 (VR30DDTT)
• Note: Does not fit 2.0L Turbo or 3.5L Hybrid models.

Frequently Asked Questions

Does this fit the V37 Q50?

Yes, this is a direct fit for the 2016-2021 Infiniti Q50 equipped with the VR30DDTT twin-turbo engine.

Do both cooling circuits need to be vacuum-bled after installation?

Yes, both the primary engine cooling loop and the intercooler circuit must be completely drained, refilled, and bled of air to maintain correct operational pressures.

The Infiniti Performance Standard

Engineered to handle high-output twin-turbo power delivery, this metal expansion tank ensures your turbocharged V6 maintains closed-loop cooling stability under high boost without the risk of thermal fatigue or brittle plastic failures.