IAG Threaded Plugs for FA Cylinder Heads (Set of 8) WRX 15-21 / FR-S / BRZ 13-20| IAG-ENG-2020

Product Fitment:

2015-2021 Subaru WRX

2013-2020 Subaru BRZ

2013-2016 Scion FR-S

Prevent catastrophic coolant and oil contamination issues with the IAG FA20 Cylinder Head Threaded Freeze Plug Upgrade. The FA20 engine’s OEM pressed-in freeze plugs are notorious for falling out under heat and pressure, especially in high-performance or modified setups. IAG's solution? Replace them with reliable threaded zinc-plated plugs that are precision-machined and sealed to last.

From the factory, FA20 heads use soft, pressed-in freeze plugs that can leak externally or internally, allowing coolant to mix with oil—a potential disaster. Even stock cars are at risk. The worst part? Most of these plugs are hidden behind timing and valve covers, so failures often go unnoticed until it’s too late.

IAG removes these failure-prone plugs and replaces them with threaded plugs, a proven fix used in all IAG FA cylinder head packages. This service adds strength and long-term reliability for both street and race engines.

Features:

• Eliminates OEM Freeze Plug Failures
  Prevents coolant leaks and internal contamination issues.

• Precision-Machined Threads
  Threads are cut into (x4) locations on each cylinder head to accept durable threaded plugs.

• Durable Zinc-Plated Plugs
  Designed for long-lasting corrosion resistance and optimal sealing.

Included

• (x8) Zinc-plated threaded plugs

Installation details:

• Cylinder heads must be removed from the engine

• Machine threading required – professional machining service strongly recommended

• Use Loctite 577 (not included) for sealant

• Torque spec: 55 N·m