The Subaru FA20 cylinder heads use pressed-in freeze plugs from the factory. It's common for the plugs to fall out, lose coolant externally or even internally into the oil. Unfortunately, most of the freeze plugs are located behind the timing cover and valve covers, so you would never know if they popped out. This can happen on OEM cars as well as cars with performance upgrades causing a number issues that could be catastrophic.

To solve the issue, the failure prone pressed-in freeze plugs are removed from the cylinder heads and threaded plugs are added in place. IAG provides the threaded plug upgrade on all of our FA cylinder head packages. In order to install the plugs IAG machine threads into (x4) freeze plug locations on each cylinder head. IAG offers the machine service separately (Service# IAG-MSS-2920).

Includes:

• (x8) Threaded zinc plated plugs  

Install Recommendations:

• Heads must be removed from the long block and require machine threading
• Professional Machining Services Required
• Professional Install Recommended
• Loctite 577 is required for install (Not Included)
• Plugs should be torqued to 55 N.m