used 6 cyl. shroud, new radiator and new trans cooler and yes, new thermostat as the whole engine was stripped back to bare bones and rebuilt with all new stuff. thing is, it's been running fine, its only now that the weather is getting warmer that it's starting to heat up... i think the thermostat works, as even when it was cooler weather (cold melb weather that is), it fluctuated by a millimeter or so... it was was opening and closing. But now, it's going way over half way... to almost up the top white line and i really don't want to cook my nice new motor....