RCM Cylinder 4 Cooling Mod Kit - Motorsport Spec
Cylinder 4 cooling has long been a recognised weakness of the Subaru EJ engine family.
Due to the design of the water passageways in this area, coolant flow around cylinder 4 can be limited, leading to elevated localised temperatures. Over time, this can contribute to increased thermal stress and potential engine issues. RCM’s simple and effective solution addresses this problem with an easy-to-install, complete kit.
Our kit utilises billet fittings securely banded to a custom 90-degree Samco silicone hose. This assembly fits directly into the unused coolant port at the rear of the block, precisely at cylinder 4’s location. The hose is then tee’d into the water matrix pipe above using the supplied Hi-Grip stainless steel clamps.
The billet barb fitting is carefully sized to provide the correct coolant flow rate—improving cooling around cylinder 4 without the risk of over-cooling. The pre-formed 90-degree Samco hose ensures consistent, unrestricted flow while eliminating the risk of kinks commonly associated with universal hose routing.
Description
Cylinder 4 cooling has long been a recognised weakness of the Subaru EJ engine family.
Due to the design of the water passageways in this area, coolant flow around cylinder 4 can be limited, leading to elevated localised temperatures. Over time, this can contribute to increased thermal stress and potential engine issues. RCM’s simple and effective solution addresses this problem with an easy-to-install, complete kit.
Our kit utilises billet fittings securely banded to a custom 90-degree Samco silicone hose. This assembly fits directly into the unused coolant port at the rear of the block, precisely at cylinder 4’s location. The hose is then tee’d into the water matrix pipe above using the supplied Hi-Grip stainless steel clamps.
The billet barb fitting is carefully sized to provide the correct coolant flow rate—improving cooling around cylinder 4 without the risk of over-cooling. The pre-formed 90-degree Samco hose ensures consistent, unrestricted flow while eliminating the risk of kinks commonly associated with universal hose routing.
