Hi , I need some help in solving a problem . I have a 351 c 2 v , its fitted in my land cruiser . I have severe over heating problems . So here is the scenario , I have no overheating probs when it's idling , it will stay around 75 deg c . When I Drive it hard it will boil over @120 deg c . These are the things I've done so far , new ally radiator suit xw 351 , new 17" flex fan , correct thermostat ( dayco DT66A ) , high flow water pump , thermo fan on front of radiator , and finally a full fan shroud . Any ideas , I have a theory the flex fan is flatning out stopping air flow at higher revs . Thanks Dazza

Just a few questions to eliminate possible causes:

1. Are you using a good quality coolant? Using a 30-50% mix?

2. Is your high flow water pump electric?

3. Any chance the radiator core is faulty and not letting the coolant through fast enough?
I'd expect this from a Chinese made product.

4. Have you tried running it without the flex fan and just using the thermo fan?

5. When is the thermo fan set to turn on?

Is the electric fan going the correct direction, is there good coolant flow through the engine and radiator?

I would look at deleting the engine fan and fitting a good Twin Thermo Fan (EF/EL/AU) or large single fan as fitted to some of the B series Falcons on the inside of the engine bay. Then there is no restriction to the airflow.

Also fit the largest radiator that you can into the space allowed.

whats your ignition timing curve look like?

Thanks everyone , I took the car 'tis radiator specialist , he checked it all out . He found the radiator way too small . New radiator ,cost a lot and no more overheating . Chinese radiators be careful , anadvertised 3 core may not be what gets delivered .