I put together a Mini me (D15B7 with Y8 head intake and header P28 ECU)
The engine runs smooth as silk at any speed (RPM's) but, after 3000 RPM spils coolant thru the coolant reservoir, hot or cold, you can leave it running for up to an hour below 3000 rpm no problem, but if you pass 3000 rpm it looses coolant and eventually overheats, Radiator it's brand new, radiator cap too but I removed the thermostat this morning but t does the same thing, spills coolant, I did my homework (search) but couldn't find any info about this issue, I hope somebody can help me, cooling fan it's working properly, I even hot wired, so it runs all the time if I don't disconnect it.

Thanks

 

Have the same problem...