The factory expansion tank on a turbo Subaru is a plastic part living in a hot engine bay, and repeated heat cycles are what eventually split it. This fabricated aluminum replacement bolts into the same location, holds about half again as much coolant, and looks like a deliberate modification rather than a patch.

Moroso 63784 Intercooler Expansion Tank Features:

• Direct bolt-in replacement for the factory tank, no fabrication required.
• Dual tanks mount in the factory single-tank location.
• Fabricated aluminum construction for strength and long service life.
• Approximately 50 percent more capacity than the factory tank.
• Includes a 14-18 psi cap and integral billet aluminum hose fittings.
• Can be run as-is or polished, chromed or powder coated.