Hey guys just put a Mishi Moto radiator in my 06STI I swap the Caps around as suggested but it’s still overheating really bad any suggestions on what I should try

 

put a 'proper' radiator in..........

if its just been installled most likely you have an airlock so would pursue this first

 

So it wasn't over hearing before?

 

no it wasn’t

 

Mishimoto haven't a great reputation. As Stockcar say explore airlock first. Drain and refill.

 

Brand new header tank bought and leaked from weld mishi****o neve4 again...

there’s nowt wrong with stock to bout 400bhp ish and the bigger aftermarket ones only create more heat in the engine Bay Area imo

 

I have found Subaru’s can be a mare to burp coolant. Especially with bigger rads for some reason. I find this an essential tool to do it easily and quickly

I fitted a Mishimoto rad to my 2009 STi. I did have a few issues with the drain plug and the upper fitting leaking.. But a bit of sealant a decent quality O-ring sorted that.
The reason I fitted a new rad was because mine ran rather warm all the time. I done new thermostat and hoses but this didn’t help either. What I found on mine was the AC condenser that sits in front of the rad all the fins had furred up really badly stopping airflow. Since replacing that now sits at a solid 84c all day long no matter how I drive it. Could be worth checking yours