With our filter bases mounted, we could then route the return line from the coolant filter base to the overflow hose that routes from the top of our radiator to the Degas bottle mounted at the firewall. Before cutting and splicing into the cooling system, we made sure to drain our cooling system through the radiator petcock found on the lower driver side corner. Since our coolant had just recently been flushed and serviced, we opted to drain into clean buckets so it could be reused, but if it’s been awhile since your cooling system was serviced, this is the perfect time to recycle the used coolant and refill with new once the job is complete. The small hose just needs to be cut near the radiator and spliced into. The kit includes the small brass tee and hose clamps to make this an easy, leak-free connection.
The routing of the return line runs it directly across the top of our fan shroud, where it will be protected from any moving engine parts, but to err on the safe side, Sinister also includes a small plastic hose retainer that is installed around the hose and stuck into a small 1/4-inch drilled into the shroud.