Im going to try to explain everything in this post that I have done in the last couple months in which ive had this sporadic overheating problem. Ok, I bought an 87 mk3 with a rebuilt engine with 40 over pistons and arp studs, stock turbo, 3'' custom exhaust, hks MHG, pretty new core radiator, XS power fmic, NO thermostat, and everything else stock besides an electric fan. I bought and installed a 60 trim ct26 and started having overheating problems shortly after when on the highway for extended periods of time if I slowed down and got off an exit ramp. I bled the system thoroughly but it didnt do anything. I then realized that the previous owner had the relay wires wired wrong making it blow the wrong way. I thought for sure this solved my problem but sure enough it still overheated on cue when I got off the exit ramp after sitting still in traffic. Other than being on the highway, it NEVER overheated. A couple days later, it was overheating again on the highway so I pulled over and popped the hood. Literally 10 seconds later, the hose connecting to the heater valve popped off and all the coolant came out. I then considered that the bigger turbo needed more air so I bought a stock clutch fan and installed it that night. The next day, I turned the car on and I had smoke out of the exhaust and smoke/steam coming from the turbo where it connects to the exhaust and downpipe. The turbo was so hot it was glowing red... Anyways, could not having a thermostat be the problem? I recently disconnected the coolant lines and there was plenty of coolant getting in to the turbo. Or could my water pump be bad? After all, more problems did occur immediately after installing the clutch fan. Thanks again guys, your input is really appreciated.