The background to my overheating was that it only ever occurred at relatively low speeds, like below 80km/h above that and the temps were fine. Long story short was that when I first got the car in the middle of winter it wouldn't get up to temperature, not even warm. My solution was to change the fluid and put a new stat it in it. All seemed fine, though the next summer it ran a touch warmer than ideal in traffic, but on track and at open road speeds it was fine. This year it is warmer again, or perhaps I have been in heavier traffic for longer - you never know in Christchurch!! In discussion with Scott the 3 holes is a common technique they use on 3SGE's and I suspect that my old thermostat had at least that, probably more in it. Before getting to that solution I:nz_climber wrote:Sounds like something is not right in the cooling system. Is the thermostat opening correctly? as you should only need 1 hole just to help bleed air out of the system. Also sounds like the fan is not coming at right time either. My temp doesn't even get that high when on the track!
a) Checked that the fan was running, and running in the correct direction
b) The fan also has a manual on switch that didn't prevent the temp rising
c) Changed the coolant
d) Flushed the radiator
e) Checked the flow through the rad
f) Changed the temp sender
The water pump is listed on the parts used when the engine was rebuilt a few thousand k's ago so not a likely cause. Appreciate it isn't the ultimate solution, but obviously one others have used and I am on the road again which is good.