overheating 1UZ - where to troubleshoot?

[thechuckster]

i'm helping a fellow club member (TCC Qld) sort out an overheating MA70 with 1UZ.

motor's behaving ok when not under load (cruise/idle) but put it under load (climbing hills, aggressive driving) and the thing overheats and thermos go on 100%.

It's got a new radiator (4 core, tanks on the side), 2 thermo fans and the plumbing setup correctly to the adiator (assuming the pipes to the radiator in this pic are correct).

Given that i'm not familiar with this engine (for starters, the coolant flowing back thru the thermostat is a bit of a surprise) i'd like any pointers as to where to look next.

I think the thermostat needs looking at again (any clue as to what temp they should open up at) - owner claims it is a new item.

I also think bleeding (again) would be a good idea.

Anywhere else we should be looking?

cheers and tia,
Charles.

[lojik]

This: suggests they should open at 82deg.

Air bubbles in the coolant pipes?

good luck

[SilverGhost]

the body of the thermostat should always be on the motor side of the pipe so it gets first hand heat from the motor and opens accordingly.

If you have it backwards, or the pipes hooked up incorrectly the hot coolant might not be reaching the right side of the thermostat so it never really opens properly. That would be my first guess....