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Discussion Starter · #1 ·
the car is a 2002 ZX5, with a 2.0 Zetec and a built motor
it has a 180 degree thermostat
and I have changed the following parts in the last while
Radiator, thermostat, Coolant, water pump

driving on the highway at around 120Kph the car runs at between 190-208 depending on the hills

on a steep grade I can easilly hit 220 degrees

however if I do a WOT run through 3 and 4th gears and wind it up to about 140-160kph the temp I can watch the temp go up and i usually bail out before 220 but it will continue upward to about 230 sometimes higher and then within 10 seconds of no throttle it will be back down to 200
the only thing I havent changed is the temp sensor, which i may change this weekend
there is no water in the oil, oil in the water and the fluids are clean, I'm not using an underdrive pulley either
the radiator is boxed as well

any ideas what to try next?
Thanks..
 

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oh and A/F is around 10.8 at WOT
That seems a bit rich to me, but for this specific issue, should help with lowering coolant temps.

I can’t be the only one :).
at 220-240 degrees will it be boiling the antifreeze? Because it isn’t
Nah, the pressure in the system increases the boiling point. For a 50/50 mix, you're looking near 260* before it'll boil. How are you datalogging coolant temps? Are you doing this via SCT and the cylinder head temp sensor, or with a proper coolant temp gauge?
 

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Discussion Starter · #6 ·
I'm using the SCT X4 and logging coolant temp which I believe the the Cylinder Head Sensor.
 

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2004 ZX3 SVT EE. 2004 ZX3 SVT
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Cylinder head temp sensor failure is common due to corrosion at the connector and age. I wouldn't trust an old one on a turbo build.
 
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