So, I have to tell a story.
I live in a mountain and i have a european modell IS 250(RWD). 2006, with 165.000km with full extra and full service book so everything must be fine. But...
It is in Italy, Meran. Hot summer days and yeah the road up to the mountain to my home is 13-14km from the city.
I have this car since 2016 summer and no problem with it.
I got this job in the mountain and since from the first time my car will every time overheating if i climb the mountain.
It is always different. Sometime it is only 110C but sometimes if outside is too hot than 130C or almost in the Red line.
I have to always turn on the heater core on full open(classic trick).
So read many many topics and videos. I checked the leaks or maybe a bad head gasket or something. But nothing...

- Changed the thermostat(the old was also fine, i have tested) - Nothing happend
- Changed the oil(i read somewhere it could be also a problem) - Nothing
- Changed the coolant - Nothing
Than i realized, the radiator cap was broken so i changed it but always yet - Nothing happend
Than i wrote a big comment in a topic somewhere and somebody said "get out the radiator and from outside or if its need than also inside wash it."
Okay, let's try...why not...
- I taked out the radiator and i got this what you see in the pictures!!
My good...i haven't seen like this before...
So, yeah 11 yeras old car, everything works fine in a normal road but on the mountain you become every little **** immediatelly.
Might be never was washed this radiator...
So i washed it. Put everything back and now works fine
36C is outside. I have found a way long road up to the mountain and nothing happens Max 96C and than the ventilators come on for 20 second and that's all

So i prefer for everybody to check this out If your car is overheated!!

And another featuer...Before i put it out i checked from the front bumper how it looks(really i must have it out or not...?) And from the front bumper it looks like clean! But not....
And another thing...the climate radiator is front of the normal radiator(picture) and the climate radiator has bigger holes than the normal one...thats why it looks clean and the thing is...it is clean!
So dont be tired. Get it out and **** off overheating

P.S.: The ventilator at working was so loud. Now are quiet

http://www.lexusownersclub.co.uk/for...0-overheating/

 

Thanks for posting your story! Bottomline, clean your radiator.