So, I drilled and tapped for the "de-gas" burp valve on the coolant outlet of the engine. It is a 1/8 -27 NPT hose barb and ran the 5/16" hose up to an aftermarket coolant expansion tank I got on eBay.



I also got the 137kPA OEM radiator cap, and an adaptor to run a second "de-gas" burp hose from the radiator to the coolant expansion tank like the turbo models already have.





On the lower 1/2" outlet on the coolant expansion tank I ran a 1/2" to the return line on the heater hoses (blue)



This set up seems to work after 10 miles. coolant was coming out of the 5/16" outlet next to the cap so I ran a hose from that to the overflow tank I had left over from my mk4 build (lower yellow arrow)



I have not drilled a hole in the thermostat. After another 10 miles I don't seem to have any coolant leaks and no overheating!


I bought an aftermarket